diff --git a/Source/Core/DiscIO/CompressedBlob.cpp b/Source/Core/DiscIO/CompressedBlob.cpp
index 74427c95a1..bd3a05806b 100644
--- a/Source/Core/DiscIO/CompressedBlob.cpp
+++ b/Source/Core/DiscIO/CompressedBlob.cpp
@@ -316,8 +316,9 @@ bool DecompressBlobToFile(const std::string& infile, const std::string& outfile,
 	const CompressedBlobHeader &header = reader->GetHeader();
 	static const size_t BUFFER_BLOCKS = 32;
 	size_t buffer_size = header.block_size * BUFFER_BLOCKS;
+	size_t last_buffer_size = header.block_size * (header.num_blocks % BUFFER_BLOCKS);
 	std::vector<u8> buffer(buffer_size);
-	u32 num_buffers = header.num_blocks / BUFFER_BLOCKS;
+	u32 num_buffers = (header.num_blocks + BUFFER_BLOCKS - 1) / BUFFER_BLOCKS;
 	int progress_monitor = std::max<int>(1, num_buffers / 100);
 	bool was_cancelled = false;
 
@@ -329,8 +330,9 @@ bool DecompressBlobToFile(const std::string& infile, const std::string& outfile,
 			if (was_cancelled)
 				break;
 		}
-		reader->Read(i * buffer_size, buffer_size, buffer.data());
-		f.WriteBytes(buffer.data(), buffer_size);
+		const size_t sz = i == num_buffers - 1 ? last_buffer_size : buffer_size;
+		reader->Read(i * buffer_size, sz, buffer.data());
+		f.WriteBytes(buffer.data(), sz);
 	}
 
 	if (was_cancelled)