diff --git a/Source/Core/DiscIO/Blob.cpp b/Source/Core/DiscIO/Blob.cpp
index d7aad9332a..7d30cfe212 100644
--- a/Source/Core/DiscIO/Blob.cpp
+++ b/Source/Core/DiscIO/Blob.cpp
@@ -7,6 +7,7 @@
 #include <limits>
 #include <memory>
 #include <string>
+#include <utility>
 
 #include "Common/CDUtils.h"
 #include "Common/CommonTypes.h"
@@ -177,23 +178,31 @@ std::unique_ptr<IBlobReader> CreateBlobReader(const std::string& filename)
   if (cdio_is_cdrom(filename))
     return DriveReader::Create(filename);
 
-  if (!File::Exists(filename))
+  File::IOFile file(filename, "rb");
+  u32 magic;
+  if (!file.ReadArray(&magic, 1))
     return nullptr;
 
-  if (IsWbfsBlob(filename))
-    return WbfsFileReader::Create(filename);
+  // Conveniently, every supported file format (except for plain disc images) starts
+  // with a 4-byte magic number that identifies the format, so we just need a simple
+  // switch statement to create the right blob type. If the magic number doesn't
+  // match any known magic number, we assume it's a plain disc image. If that
+  // assumption is wrong, the volume code that runs later will notice the error
+  // because the blob won't provide valid data when reading the GC/Wii disc header.
 
-  if (IsGCZBlob(filename))
-    return CompressedBlobReader::Create(filename);
-
-  if (IsCISOBlob(filename))
-    return CISOFileReader::Create(filename);
-
-  if (IsTGCBlob(filename))
-    return TGCFileReader::Create(filename);
-
-  // Still here? Assume plain file - since we know it exists due to the File::Exists check above.
-  return PlainFileReader::Create(filename);
+  switch (magic)
+  {
+  case CISO_MAGIC:
+    return CISOFileReader::Create(std::move(file));
+  case GCZ_MAGIC:
+    return CompressedBlobReader::Create(std::move(file), filename);
+  case TGC_MAGIC:
+    return TGCFileReader::Create(std::move(file));
+  case WBFS_MAGIC:
+    return WbfsFileReader::Create(std::move(file), filename);
+  default:
+    return PlainFileReader::Create(std::move(file));
+  }
 }
 
 }  // namespace
diff --git a/Source/Core/DiscIO/Blob.h b/Source/Core/DiscIO/Blob.h
index fa068c33ef..7f954cd65b 100644
--- a/Source/Core/DiscIO/Blob.h
+++ b/Source/Core/DiscIO/Blob.h
@@ -159,10 +159,10 @@ std::unique_ptr<IBlobReader> CreateBlobReader(const std::string& filename);
 
 typedef bool (*CompressCB)(const std::string& text, float percent, void* arg);
 
-bool CompressFileToBlob(const std::string& infile, const std::string& outfile, u32 sub_type = 0,
-                        int sector_size = 16384, CompressCB callback = nullptr,
+bool CompressFileToBlob(const std::string& infile_path, const std::string& outfile_path,
+                        u32 sub_type = 0, int sector_size = 16384, CompressCB callback = nullptr,
                         void* arg = nullptr);
-bool DecompressBlobToFile(const std::string& infile, const std::string& outfile,
+bool DecompressBlobToFile(const std::string& infile_path, const std::string& outfile_path,
                           CompressCB callback = nullptr, void* arg = nullptr);
 
 }  // namespace
diff --git a/Source/Core/DiscIO/CISOBlob.cpp b/Source/Core/DiscIO/CISOBlob.cpp
index 37e427793b..846952ce8a 100644
--- a/Source/Core/DiscIO/CISOBlob.cpp
+++ b/Source/Core/DiscIO/CISOBlob.cpp
@@ -5,6 +5,7 @@
 #include <algorithm>
 #include <cstdio>
 #include <memory>
+#include <utility>
 
 #include "Common/CommonTypes.h"
 #include "Common/FileUtil.h"
@@ -12,13 +13,12 @@
 
 namespace DiscIO
 {
-static const char CISO_MAGIC[] = "CISO";
-
-CISOFileReader::CISOFileReader(std::FILE* file) : m_file(file)
+CISOFileReader::CISOFileReader(File::IOFile file) : m_file(std::move(file))
 {
   m_size = m_file.GetSize();
 
   CISOHeader header;
+  m_file.Seek(0, SEEK_SET);
   m_file.ReadArray(&header, 1);
 
   m_block_size = header.block_size;
@@ -28,13 +28,11 @@ CISOFileReader::CISOFileReader(std::FILE* file) : m_file(file)
     m_ciso_map[idx] = (1 == header.map[idx]) ? count++ : UNUSED_BLOCK_ID;
 }
 
-std::unique_ptr<CISOFileReader> CISOFileReader::Create(const std::string& filename)
+std::unique_ptr<CISOFileReader> CISOFileReader::Create(File::IOFile file)
 {
-  if (IsCISOBlob(filename))
-  {
-    File::IOFile f(filename, "rb");
-    return std::unique_ptr<CISOFileReader>(new CISOFileReader(f.ReleaseHandle()));
-  }
+  CISOHeader header;
+  if (file.Seek(0, SEEK_SET) && file.ReadArray(&header, 1) && header.magic == CISO_MAGIC)
+    return std::unique_ptr<CISOFileReader>(new CISOFileReader(std::move(file)));
 
   return nullptr;
 }
@@ -81,13 +79,4 @@ bool CISOFileReader::Read(u64 offset, u64 nbytes, u8* out_ptr)
   return true;
 }
 
-bool IsCISOBlob(const std::string& filename)
-{
-  File::IOFile f(filename, "rb");
-
-  CISOHeader header;
-  return (f.ReadArray(&header, 1) &&
-          std::equal(header.magic, header.magic + sizeof(header.magic), CISO_MAGIC));
-}
-
 }  // namespace
diff --git a/Source/Core/DiscIO/CISOBlob.h b/Source/Core/DiscIO/CISOBlob.h
index 9eed0d992a..b8c0ebd816 100644
--- a/Source/Core/DiscIO/CISOBlob.h
+++ b/Source/Core/DiscIO/CISOBlob.h
@@ -14,7 +14,7 @@
 
 namespace DiscIO
 {
-bool IsCISOBlob(const std::string& filename);
+static constexpr u32 CISO_MAGIC = 0x4F534943;  // "CISO" (byteswapped to little endian)
 
 static const u32 CISO_HEADER_SIZE = 0x8000;
 static const u32 CISO_MAP_SIZE = CISO_HEADER_SIZE - sizeof(u32) - sizeof(char) * 4;
@@ -22,7 +22,7 @@ static const u32 CISO_MAP_SIZE = CISO_HEADER_SIZE - sizeof(u32) - sizeof(char) *
 struct CISOHeader
 {
   // "CISO"
-  char magic[4];
+  u32 magic;
 
   // little endian
   u32 block_size;
@@ -34,7 +34,7 @@ struct CISOHeader
 class CISOFileReader : public IBlobReader
 {
 public:
-  static std::unique_ptr<CISOFileReader> Create(const std::string& filename);
+  static std::unique_ptr<CISOFileReader> Create(File::IOFile file);
 
   BlobType GetBlobType() const override { return BlobType::CISO; }
   // The CISO format does not save the original file size.
@@ -45,7 +45,7 @@ public:
   bool Read(u64 offset, u64 nbytes, u8* out_ptr) override;
 
 private:
-  CISOFileReader(std::FILE* file);
+  CISOFileReader(File::IOFile file);
 
   typedef u16 MapType;
   static const MapType UNUSED_BLOCK_ID = -1;
diff --git a/Source/Core/DiscIO/CompressedBlob.cpp b/Source/Core/DiscIO/CompressedBlob.cpp
index 680ca8d179..0cf8dbc5b3 100644
--- a/Source/Core/DiscIO/CompressedBlob.cpp
+++ b/Source/Core/DiscIO/CompressedBlob.cpp
@@ -13,6 +13,7 @@
 #include <cstring>
 #include <memory>
 #include <string>
+#include <utility>
 #include <vector>
 #include <zlib.h>
 
@@ -28,10 +29,13 @@
 
 namespace DiscIO
 {
-CompressedBlobReader::CompressedBlobReader(const std::string& filename) : m_file_name(filename)
+bool IsGCZBlob(File::IOFile& file);
+
+CompressedBlobReader::CompressedBlobReader(File::IOFile file, const std::string& filename)
+    : m_file(std::move(file)), m_file_name(filename)
 {
-  m_file.Open(filename, "rb");
-  m_file_size = File::GetSize(filename);
+  m_file_size = m_file.GetSize();
+  m_file.Seek(0, SEEK_SET);
   m_file.ReadArray(&m_header, 1);
 
   SetSectorSize(m_header.block_size);
@@ -53,10 +57,12 @@ CompressedBlobReader::CompressedBlobReader(const std::string& filename) : m_file
   m_zlib_buffer.resize(zlib_buffer_size);
 }
 
-std::unique_ptr<CompressedBlobReader> CompressedBlobReader::Create(const std::string& filename)
+std::unique_ptr<CompressedBlobReader> CompressedBlobReader::Create(File::IOFile file,
+                                                                   const std::string& filename)
 {
-  if (IsGCZBlob(filename))
-    return std::unique_ptr<CompressedBlobReader>(new CompressedBlobReader(filename));
+  if (IsGCZBlob(file))
+    return std::unique_ptr<CompressedBlobReader>(
+        new CompressedBlobReader(std::move(file), filename));
 
   return nullptr;
 }
@@ -145,40 +151,41 @@ bool CompressedBlobReader::GetBlock(u64 block_num, u8* out_ptr)
   return true;
 }
 
-bool CompressFileToBlob(const std::string& infile, const std::string& outfile, u32 sub_type,
-                        int block_size, CompressCB callback, void* arg)
+bool CompressFileToBlob(const std::string& infile_path, const std::string& outfile_path,
+                        u32 sub_type, int block_size, CompressCB callback, void* arg)
 {
   bool scrubbing = false;
 
+  File::IOFile infile(infile_path, "rb");
   if (IsGCZBlob(infile))
   {
-    PanicAlertT("\"%s\" is already compressed! Cannot compress it further.", infile.c_str());
+    PanicAlertT("\"%s\" is already compressed! Cannot compress it further.", infile_path.c_str());
     return false;
   }
 
-  File::IOFile inf(infile, "rb");
-  if (!inf)
+  if (!infile)
   {
-    PanicAlertT("Failed to open the input file \"%s\".", infile.c_str());
+    PanicAlertT("Failed to open the input file \"%s\".", infile_path.c_str());
     return false;
   }
 
-  File::IOFile f(outfile, "wb");
-  if (!f)
+  File::IOFile outfile(outfile_path, "wb");
+  if (!outfile)
   {
     PanicAlertT("Failed to open the output file \"%s\".\n"
                 "Check that you have permissions to write the target folder and that the media can "
                 "be written.",
-                outfile.c_str());
+                outfile_path.c_str());
     return false;
   }
 
   DiscScrubber disc_scrubber;
   if (sub_type == 1)
   {
-    if (!disc_scrubber.SetupScrub(infile, block_size))
+    if (!disc_scrubber.SetupScrub(infile_path, block_size))
     {
-      PanicAlertT("\"%s\" failed to be scrubbed. Probably the image is corrupt.", infile.c_str());
+      PanicAlertT("\"%s\" failed to be scrubbed. Probably the image is corrupt.",
+                  infile_path.c_str());
       return false;
     }
 
@@ -192,10 +199,10 @@ bool CompressFileToBlob(const std::string& infile, const std::string& outfile, u
   callback(GetStringT("Files opened, ready to compress."), 0, arg);
 
   CompressedBlobHeader header;
-  header.magic_cookie = kBlobCookie;
+  header.magic_cookie = GCZ_MAGIC;
   header.sub_type = sub_type;
   header.block_size = block_size;
-  header.data_size = File::GetSize(infile);
+  header.data_size = infile.GetSize();
 
   // round upwards!
   header.num_blocks = (u32)((header.data_size + (block_size - 1)) / block_size);
@@ -206,9 +213,9 @@ bool CompressFileToBlob(const std::string& infile, const std::string& outfile, u
   std::vector<u8> in_buf(block_size);
 
   // seek past the header (we will write it at the end)
-  f.Seek(sizeof(CompressedBlobHeader), SEEK_CUR);
+  outfile.Seek(sizeof(CompressedBlobHeader), SEEK_CUR);
   // seek past the offset and hash tables (we will write them at the end)
-  f.Seek((sizeof(u64) + sizeof(u32)) * header.num_blocks, SEEK_CUR);
+  outfile.Seek((sizeof(u64) + sizeof(u32)) * header.num_blocks, SEEK_CUR);
 
   // Now we are ready to write compressed data!
   u64 position = 0;
@@ -221,7 +228,7 @@ bool CompressFileToBlob(const std::string& infile, const std::string& outfile, u
   {
     if (i % progress_monitor == 0)
     {
-      const u64 inpos = inf.Tell();
+      const u64 inpos = infile.Tell();
       int ratio = 0;
       if (inpos != 0)
         ratio = (int)(100 * position / inpos);
@@ -241,9 +248,9 @@ bool CompressFileToBlob(const std::string& infile, const std::string& outfile, u
 
     size_t read_bytes;
     if (scrubbing)
-      read_bytes = disc_scrubber.GetNextBlock(inf, in_buf.data());
+      read_bytes = disc_scrubber.GetNextBlock(infile, in_buf.data());
     else
-      inf.ReadArray(in_buf.data(), header.block_size, &read_bytes);
+      infile.ReadArray(in_buf.data(), header.block_size, &read_bytes);
     if (read_bytes < header.block_size)
       std::fill(in_buf.begin() + read_bytes, in_buf.begin() + header.block_size, 0);
 
@@ -283,11 +290,11 @@ bool CompressFileToBlob(const std::string& infile, const std::string& outfile, u
       num_compressed++;
     }
 
-    if (!f.WriteBytes(write_buf, write_size))
+    if (!outfile.WriteBytes(write_buf, write_size))
     {
       PanicAlertT("Failed to write the output file \"%s\".\n"
                   "Check that you have enough space available on the target drive.",
-                  outfile.c_str());
+                  outfile_path.c_str());
       success = false;
       break;
     }
@@ -302,16 +309,16 @@ bool CompressFileToBlob(const std::string& infile, const std::string& outfile, u
   if (!success)
   {
     // Remove the incomplete output file.
-    f.Close();
-    File::Delete(outfile);
+    outfile.Close();
+    File::Delete(outfile_path);
   }
   else
   {
     // Okay, go back and fill in headers
-    f.Seek(0, SEEK_SET);
-    f.WriteArray(&header, 1);
-    f.WriteArray(offsets.data(), header.num_blocks);
-    f.WriteArray(hashes.data(), header.num_blocks);
+    outfile.Seek(0, SEEK_SET);
+    outfile.WriteArray(&header, 1);
+    outfile.WriteArray(offsets.data(), header.num_blocks);
+    outfile.WriteArray(hashes.data(), header.num_blocks);
   }
 
   // Cleanup
@@ -324,29 +331,34 @@ bool CompressFileToBlob(const std::string& infile, const std::string& outfile, u
   return success;
 }
 
-bool DecompressBlobToFile(const std::string& infile, const std::string& outfile,
+bool DecompressBlobToFile(const std::string& infile_path, const std::string& outfile_path,
                           CompressCB callback, void* arg)
 {
-  if (!IsGCZBlob(infile))
+  std::unique_ptr<CompressedBlobReader> reader;
   {
-    PanicAlertT("File not compressed");
-    return false;
+    File::IOFile infile(infile_path, "rb");
+    if (!IsGCZBlob(infile))
+    {
+      PanicAlertT("File not compressed");
+      return false;
+    }
+
+    reader = CompressedBlobReader::Create(std::move(infile), infile_path);
   }
 
-  std::unique_ptr<CompressedBlobReader> reader(CompressedBlobReader::Create(infile));
   if (!reader)
   {
-    PanicAlertT("Failed to open the input file \"%s\".", infile.c_str());
+    PanicAlertT("Failed to open the input file \"%s\".", infile_path.c_str());
     return false;
   }
 
-  File::IOFile f(outfile, "wb");
-  if (!f)
+  File::IOFile outfile(outfile_path, "wb");
+  if (!outfile)
   {
     PanicAlertT("Failed to open the output file \"%s\".\n"
                 "Check that you have permissions to write the target folder and that the media can "
                 "be written.",
-                outfile.c_str());
+                outfile_path.c_str());
     return false;
   }
 
@@ -372,11 +384,11 @@ bool DecompressBlobToFile(const std::string& infile, const std::string& outfile,
     }
     const size_t sz = i == num_buffers - 1 ? last_buffer_size : buffer_size;
     reader->Read(i * buffer_size, sz, buffer.data());
-    if (!f.WriteBytes(buffer.data(), sz))
+    if (!outfile.WriteBytes(buffer.data(), sz))
     {
       PanicAlertT("Failed to write the output file \"%s\".\n"
                   "Check that you have enough space available on the target drive.",
-                  outfile.c_str());
+                  outfile_path.c_str());
       success = false;
       break;
     }
@@ -385,23 +397,21 @@ bool DecompressBlobToFile(const std::string& infile, const std::string& outfile,
   if (!success)
   {
     // Remove the incomplete output file.
-    f.Close();
-    File::Delete(outfile);
+    outfile.Close();
+    File::Delete(outfile_path);
   }
   else
   {
-    f.Resize(header.data_size);
+    outfile.Resize(header.data_size);
   }
 
   return true;
 }
 
-bool IsGCZBlob(const std::string& filename)
+bool IsGCZBlob(File::IOFile& file)
 {
-  File::IOFile f(filename, "rb");
-
   CompressedBlobHeader header;
-  return f.ReadArray(&header, 1) && (header.magic_cookie == kBlobCookie);
+  return file.Seek(0, SEEK_SET) && file.ReadArray(&header, 1) && header.magic_cookie == GCZ_MAGIC;
 }
 
 }  // namespace
diff --git a/Source/Core/DiscIO/CompressedBlob.h b/Source/Core/DiscIO/CompressedBlob.h
index 4c33cf85be..281db6c64a 100644
--- a/Source/Core/DiscIO/CompressedBlob.h
+++ b/Source/Core/DiscIO/CompressedBlob.h
@@ -23,9 +23,7 @@
 
 namespace DiscIO
 {
-bool IsGCZBlob(const std::string& filename);
-
-const u32 kBlobCookie = 0xB10BC001;
+static constexpr u32 GCZ_MAGIC = 0xB10BC001;
 
 // GCZ file structure:
 // BlobHeader
@@ -46,7 +44,8 @@ struct CompressedBlobHeader  // 32 bytes
 class CompressedBlobReader : public SectorReader
 {
 public:
-  static std::unique_ptr<CompressedBlobReader> Create(const std::string& filename);
+  static std::unique_ptr<CompressedBlobReader> Create(File::IOFile file,
+                                                      const std::string& filename);
   ~CompressedBlobReader();
   const CompressedBlobHeader& GetHeader() const { return m_header; }
   BlobType GetBlobType() const override { return BlobType::GCZ; }
@@ -56,7 +55,7 @@ public:
   bool GetBlock(u64 block_num, u8* out_ptr) override;
 
 private:
-  CompressedBlobReader(const std::string& filename);
+  CompressedBlobReader(File::IOFile file, const std::string& filename);
 
   CompressedBlobHeader m_header;
   std::vector<u64> m_block_pointers;
diff --git a/Source/Core/DiscIO/FileBlob.cpp b/Source/Core/DiscIO/FileBlob.cpp
index 7d1dabe198..3547ef658d 100644
--- a/Source/Core/DiscIO/FileBlob.cpp
+++ b/Source/Core/DiscIO/FileBlob.cpp
@@ -2,22 +2,23 @@
 // Licensed under GPLv2+
 // Refer to the license.txt file included.
 
-#include "DiscIO/FileBlob.h"
 #include <memory>
 #include <string>
+#include <utility>
+
+#include "DiscIO/FileBlob.h"
 
 namespace DiscIO
 {
-PlainFileReader::PlainFileReader(std::FILE* file) : m_file(file)
+PlainFileReader::PlainFileReader(File::IOFile file) : m_file(std::move(file))
 {
   m_size = m_file.GetSize();
 }
 
-std::unique_ptr<PlainFileReader> PlainFileReader::Create(const std::string& filename)
+std::unique_ptr<PlainFileReader> PlainFileReader::Create(File::IOFile file)
 {
-  File::IOFile f(filename, "rb");
-  if (f)
-    return std::unique_ptr<PlainFileReader>(new PlainFileReader(f.ReleaseHandle()));
+  if (file)
+    return std::unique_ptr<PlainFileReader>(new PlainFileReader(std::move(file)));
 
   return nullptr;
 }
diff --git a/Source/Core/DiscIO/FileBlob.h b/Source/Core/DiscIO/FileBlob.h
index 3a85799651..22cd614ec6 100644
--- a/Source/Core/DiscIO/FileBlob.h
+++ b/Source/Core/DiscIO/FileBlob.h
@@ -17,7 +17,7 @@ namespace DiscIO
 class PlainFileReader : public IBlobReader
 {
 public:
-  static std::unique_ptr<PlainFileReader> Create(const std::string& filename);
+  static std::unique_ptr<PlainFileReader> Create(File::IOFile file);
 
   BlobType GetBlobType() const override { return BlobType::PLAIN; }
   u64 GetDataSize() const override { return m_size; }
@@ -25,7 +25,7 @@ public:
   bool Read(u64 offset, u64 nbytes, u8* out_ptr) override;
 
 private:
-  PlainFileReader(std::FILE* file);
+  PlainFileReader(File::IOFile file);
 
   File::IOFile m_file;
   s64 m_size;
diff --git a/Source/Core/DiscIO/TGCBlob.cpp b/Source/Core/DiscIO/TGCBlob.cpp
index 85a5a854aa..886bbb6a78 100644
--- a/Source/Core/DiscIO/TGCBlob.cpp
+++ b/Source/Core/DiscIO/TGCBlob.cpp
@@ -4,6 +4,7 @@
 
 #include <memory>
 #include <string>
+#include <utility>
 
 #include "Common/CommonFuncs.h"
 #include "Common/FileUtil.h"
@@ -56,27 +57,18 @@ void Replace32(u64 offset, u64 nbytes, u8* out_ptr, u64 replace_offset, u32 repl
 
 namespace DiscIO
 {
-bool IsTGCBlob(const std::string& path)
+std::unique_ptr<TGCFileReader> TGCFileReader::Create(File::IOFile file)
 {
-  File::IOFile file(path, "rb");
-
   TGCHeader header;
-  return (file.ReadArray(&header, 1) && header.magic == Common::swap32(0xAE0F38A2));
-}
-
-std::unique_ptr<TGCFileReader> TGCFileReader::Create(const std::string& path)
-{
-  if (IsTGCBlob(path))
-  {
-    File::IOFile file(path, "rb");
+  if (file.Seek(0, SEEK_SET) && file.ReadArray(&header, 1) && header.magic == TGC_MAGIC)
     return std::unique_ptr<TGCFileReader>(new TGCFileReader(std::move(file)));
-  }
 
   return nullptr;
 }
 
-TGCFileReader::TGCFileReader(File::IOFile&& file) : m_file(std::move(file))
+TGCFileReader::TGCFileReader(File::IOFile file) : m_file(std::move(file))
 {
+  m_file.Seek(0, SEEK_SET);
   m_file.ReadArray(&m_header, 1);
   u32 header_size = Common::swap32(m_header.header_size);
   m_size = m_file.GetSize();
diff --git a/Source/Core/DiscIO/TGCBlob.h b/Source/Core/DiscIO/TGCBlob.h
index c1057afc27..86c0a85033 100644
--- a/Source/Core/DiscIO/TGCBlob.h
+++ b/Source/Core/DiscIO/TGCBlob.h
@@ -14,7 +14,7 @@
 
 namespace DiscIO
 {
-bool IsTGCBlob(const std::string& path);
+static constexpr u32 TGC_MAGIC = 0xA2380FAE;
 
 struct TGCHeader
 {
@@ -40,7 +40,7 @@ struct TGCHeader
 class TGCFileReader final : public IBlobReader
 {
 public:
-  static std::unique_ptr<TGCFileReader> Create(const std::string& filename);
+  static std::unique_ptr<TGCFileReader> Create(File::IOFile file);
 
   BlobType GetBlobType() const override { return BlobType::TGC; }
   u64 GetDataSize() const override;
@@ -48,7 +48,7 @@ public:
   bool Read(u64 offset, u64 nbytes, u8* out_ptr) override;
 
 private:
-  TGCFileReader(File::IOFile&& file);
+  TGCFileReader(File::IOFile file);
 
   bool InternalRead(u64 offset, u64 nbytes, u8* out_ptr);
 
diff --git a/Source/Core/DiscIO/WbfsBlob.cpp b/Source/Core/DiscIO/WbfsBlob.cpp
index 6acbe5d0b3..8c29d93202 100644
--- a/Source/Core/DiscIO/WbfsBlob.cpp
+++ b/Source/Core/DiscIO/WbfsBlob.cpp
@@ -7,9 +7,11 @@
 #include <cstring>
 #include <memory>
 #include <string>
+#include <utility>
 #include <vector>
 
 #include "Common/Align.h"
+#include "Common/Assert.h"
 #include "Common/CommonFuncs.h"
 #include "Common/CommonTypes.h"
 #include "Common/FileUtil.h"
@@ -23,20 +25,21 @@ static const u64 WII_SECTOR_SIZE = 0x8000;
 static const u64 WII_SECTOR_COUNT = 143432 * 2;
 static const u64 WII_DISC_HEADER_SIZE = 256;
 
-WbfsFileReader::WbfsFileReader(const std::string& filename)
-    : m_total_files(0), m_size(0), m_good(true)
+WbfsFileReader::WbfsFileReader(File::IOFile file, const std::string& path)
+    : m_size(0), m_good(false)
 {
-  if (filename.length() < 4 || !OpenFiles(filename) || !ReadHeader())
-  {
-    m_good = false;
+  if (!AddFileToList(std::move(file)))
     return;
-  }
+  OpenAdditionalFiles(path);
+  if (!ReadHeader())
+    return;
+  m_good = true;
 
   // Grab disc info (assume slot 0, checked in ReadHeader())
   m_wlba_table.resize(m_blocks_per_disc);
-  m_files[0]->file.Seek(m_hd_sector_size + WII_DISC_HEADER_SIZE /*+ i * m_disc_info_size*/,
-                        SEEK_SET);
-  m_files[0]->file.ReadBytes(m_wlba_table.data(), m_blocks_per_disc * sizeof(u16));
+  m_files[0].file.Seek(m_hd_sector_size + WII_DISC_HEADER_SIZE /*+ i * m_disc_info_size*/,
+                       SEEK_SET);
+  m_files[0].file.ReadBytes(m_wlba_table.data(), m_blocks_per_disc * sizeof(u16));
   for (size_t i = 0; i < m_blocks_per_disc; i++)
     m_wlba_table[i] = Common::swap16(m_wlba_table[i]);
 }
@@ -50,41 +53,46 @@ u64 WbfsFileReader::GetDataSize() const
   return WII_SECTOR_COUNT * WII_SECTOR_SIZE;
 }
 
-bool WbfsFileReader::OpenFiles(const std::string& filename)
+void WbfsFileReader::OpenAdditionalFiles(const std::string& path)
 {
-  m_total_files = 0;
+  if (path.length() < 4)
+    return;
+
+  _assert_(m_files.size() > 0);  // The code below gives .wbf0 for index 0, but it should be .wbfs
 
   while (true)
   {
-    auto new_entry = std::make_unique<file_entry>();
-
     // Replace last character with index (e.g. wbfs = wbf1)
-    std::string path = filename;
-    if (m_total_files != 0)
-    {
-      path[path.length() - 1] = '0' + m_total_files;
-    }
-
-    if (!new_entry->file.Open(path, "rb"))
-    {
-      return m_total_files != 0;
-    }
-
-    new_entry->base_address = m_size;
-    new_entry->size = new_entry->file.GetSize();
-    m_size += new_entry->size;
-
-    m_total_files++;
-    m_files.emplace_back(std::move(new_entry));
+    if (m_files.size() >= 10)
+      return;
+    std::string current_path = path;
+    current_path.back() = static_cast<char>('0' + m_files.size());
+    if (!AddFileToList(File::IOFile(current_path, "rb")))
+      return;
   }
 }
 
+bool WbfsFileReader::AddFileToList(File::IOFile file)
+{
+  if (!file.IsOpen())
+    return false;
+
+  const u64 file_size = file.GetSize();
+  m_files.emplace_back(std::move(file), m_size, file_size);
+  m_size += file_size;
+
+  return true;
+}
+
 bool WbfsFileReader::ReadHeader()
 {
   // Read hd size info
-  m_files[0]->file.ReadBytes(&m_header, sizeof(WbfsHeader));
-  m_header.hd_sector_count = Common::swap32(m_header.hd_sector_count);
+  m_files[0].file.Seek(0, SEEK_SET);
+  m_files[0].file.ReadBytes(&m_header, sizeof(WbfsHeader));
+  if (m_header.magic != WBFS_MAGIC)
+    return false;
 
+  m_header.hd_sector_count = Common::swap32(m_header.hd_sector_count);
   m_hd_sector_size = 1ull << m_header.hd_sector_shift;
 
   if (m_size != (m_header.hd_sector_count * m_hd_sector_size))
@@ -138,19 +146,19 @@ File::IOFile& WbfsFileReader::SeekToCluster(u64 offset, u64* available)
     u64 cluster_offset = offset & (m_wbfs_sector_size - 1);
     u64 final_address = cluster_address + cluster_offset;
 
-    for (u32 i = 0; i != m_total_files; i++)
+    for (file_entry& file_entry : m_files)
     {
-      if (final_address < (m_files[i]->base_address + m_files[i]->size))
+      if (final_address < (file_entry.base_address + file_entry.size))
       {
-        m_files[i]->file.Seek(final_address - m_files[i]->base_address, SEEK_SET);
+        file_entry.file.Seek(final_address - file_entry.base_address, SEEK_SET);
         if (available)
         {
-          u64 till_end_of_file = m_files[i]->size - (final_address - m_files[i]->base_address);
+          u64 till_end_of_file = file_entry.size - (final_address - file_entry.base_address);
           u64 till_end_of_sector = m_wbfs_sector_size - cluster_offset;
           *available = std::min(till_end_of_file, till_end_of_sector);
         }
 
-        return m_files[i]->file;
+        return file_entry.file;
       }
     }
   }
@@ -158,13 +166,13 @@ File::IOFile& WbfsFileReader::SeekToCluster(u64 offset, u64* available)
   PanicAlert("Read beyond end of disc");
   if (available)
     *available = 0;
-  m_files[0]->file.Seek(0, SEEK_SET);
-  return m_files[0]->file;
+  m_files[0].file.Seek(0, SEEK_SET);
+  return m_files[0].file;
 }
 
-std::unique_ptr<WbfsFileReader> WbfsFileReader::Create(const std::string& filename)
+std::unique_ptr<WbfsFileReader> WbfsFileReader::Create(File::IOFile file, const std::string& path)
 {
-  auto reader = std::unique_ptr<WbfsFileReader>(new WbfsFileReader(filename));
+  auto reader = std::unique_ptr<WbfsFileReader>(new WbfsFileReader(std::move(file), path));
 
   if (!reader->IsGood())
     reader.reset();
@@ -172,14 +180,4 @@ std::unique_ptr<WbfsFileReader> WbfsFileReader::Create(const std::string& filena
   return reader;
 }
 
-bool IsWbfsBlob(const std::string& filename)
-{
-  File::IOFile f(filename, "rb");
-
-  u8 magic[4] = {0, 0, 0, 0};
-  f.ReadBytes(&magic, 4);
-
-  return (magic[0] == 'W') && (magic[1] == 'B') && (magic[2] == 'F') && (magic[3] == 'S');
-}
-
 }  // namespace
diff --git a/Source/Core/DiscIO/WbfsBlob.h b/Source/Core/DiscIO/WbfsBlob.h
index b7b2323950..f2c0d4bfa7 100644
--- a/Source/Core/DiscIO/WbfsBlob.h
+++ b/Source/Core/DiscIO/WbfsBlob.h
@@ -14,12 +14,14 @@
 
 namespace DiscIO
 {
+static constexpr u32 WBFS_MAGIC = 0x53464257;  // "WBFS" (byteswapped to little endian)
+
 class WbfsFileReader : public IBlobReader
 {
 public:
   ~WbfsFileReader();
 
-  static std::unique_ptr<WbfsFileReader> Create(const std::string& filename);
+  static std::unique_ptr<WbfsFileReader> Create(File::IOFile file, const std::string& path);
 
   BlobType GetBlobType() const override { return BlobType::WBFS; }
   // The WBFS format does not save the original file size.
@@ -31,23 +33,28 @@ public:
   bool Read(u64 offset, u64 nbytes, u8* out_ptr) override;
 
 private:
-  WbfsFileReader(const std::string& filename);
+  WbfsFileReader(File::IOFile file, const std::string& path);
 
-  bool OpenFiles(const std::string& filename);
+  void OpenAdditionalFiles(const std::string& path);
+  bool AddFileToList(File::IOFile file);
   bool ReadHeader();
 
   File::IOFile& SeekToCluster(u64 offset, u64* available);
   bool IsGood() { return m_good; }
   struct file_entry
   {
+    file_entry(File::IOFile file_, u64 base_address_, u64 size_)
+        : file(std::move(file_)), base_address(base_address_), size(size_)
+    {
+    }
+
     File::IOFile file;
     u64 base_address;
     u64 size;
   };
 
-  std::vector<std::unique_ptr<file_entry>> m_files;
+  std::vector<file_entry> m_files;
 
-  u32 m_total_files;
   u64 m_size;
 
   u64 m_hd_sector_size;
@@ -58,7 +65,7 @@ private:
 #pragma pack(1)
   struct WbfsHeader
   {
-    char magic[4];
+    u32 magic;
     u32 hd_sector_count;
     u8 hd_sector_shift;
     u8 wbfs_sector_shift;
@@ -73,6 +80,4 @@ private:
   bool m_good;
 };
 
-bool IsWbfsBlob(const std::string& filename);
-
 }  // namespace