diff --git a/Source/Core/DolphinWX/ISOProperties.cpp b/Source/Core/DolphinWX/ISOProperties.cpp
index f3076c56f0..decbb3927c 100644
--- a/Source/Core/DolphinWX/ISOProperties.cpp
+++ b/Source/Core/DolphinWX/ISOProperties.cpp
@@ -899,7 +899,7 @@ void CISOProperties::OnExtractDataFromHeader(wxCommandEvent& event)
 	if (DiscIO::IsVolumeWiiDisc(OpenISO))
 	{
 		wxString Directory = m_Treectrl->GetItemText(m_Treectrl->GetSelection());
-		int partitionNum = wxAtoi(Directory.Mid(Directory.find_first_of("0123456789"), 2));
+		unsigned int partitionNum = wxAtoi(Directory.Mid(Directory.find_first_of("0123456789"), 2));
 
 		if (WiiDisc.size() > partitionNum)
 		{
diff --git a/Source/Core/VideoBackends/OGL/RasterFont.cpp b/Source/Core/VideoBackends/OGL/RasterFont.cpp
index eb288d9414..8e6ad2d6c8 100644
--- a/Source/Core/VideoBackends/OGL/RasterFont.cpp
+++ b/Source/Core/VideoBackends/OGL/RasterFont.cpp
@@ -213,7 +213,7 @@ void RasterFont::printMultilineText(const std::string& text, double start_x, dou
 			continue;
 		}
 
-		if (c < char_offset || c >= char_count+char_offset)
+		if ((u32) c < char_offset || (u32) c >= char_count+char_offset)
 			continue;
 
 		vertices[usage++] = x;
diff --git a/Source/Core/VideoCommon/BPFunctions.cpp b/Source/Core/VideoCommon/BPFunctions.cpp
index 58362f1a57..9bc9b4d3dd 100644
--- a/Source/Core/VideoCommon/BPFunctions.cpp
+++ b/Source/Core/VideoCommon/BPFunctions.cpp
@@ -161,7 +161,7 @@ void OnPixelFormatChange()
 	auto new_format = bpmem.zcontrol.pixel_format;
 
 	// no need to reinterpret pixel data in these cases
-	if (new_format == old_format || old_format == (unsigned int)-1)
+	if (new_format == old_format || old_format == PEControl::INVALID_FMT)
 		goto skip;
 
 	// Check for pixel format changes
diff --git a/Source/Core/VideoCommon/BPMemory.h b/Source/Core/VideoCommon/BPMemory.h
index b5466097ac..5332c3e8d4 100644
--- a/Source/Core/VideoCommon/BPMemory.h
+++ b/Source/Core/VideoCommon/BPMemory.h
@@ -779,14 +779,15 @@ union PEControl
 {
 	enum PixelFormat : u32
 	{
-		RGB8_Z24   = 0,
-		RGBA6_Z24  = 1,
-		RGB565_Z16 = 2,
-		Z24        = 3,
-		Y8         = 4,
-		U8         = 5,
-		V8         = 6,
-		YUV420     = 7
+		RGB8_Z24    = 0,
+		RGBA6_Z24   = 1,
+		RGB565_Z16  = 2,
+		Z24         = 3,
+		Y8          = 4,
+		U8          = 5,
+		V8          = 6,
+		YUV420      = 7,
+		INVALID_FMT = 0xffffffff, // Used by Dolphin to represent a missing value.
 	};
 
 	enum DepthFormat : u32
diff --git a/Source/Core/VideoCommon/RenderBase.cpp b/Source/Core/VideoCommon/RenderBase.cpp
index 12dc7b4bfc..8b42d1c23b 100644
--- a/Source/Core/VideoCommon/RenderBase.cpp
+++ b/Source/Core/VideoCommon/RenderBase.cpp
@@ -64,7 +64,7 @@ int Renderer::s_LastEFBScale;
 bool Renderer::s_skipSwap;
 bool Renderer::XFBWrited;
 
-PEControl::PixelFormat Renderer::prev_efb_format = (PEControl::PixelFormat)-1;
+PEControl::PixelFormat Renderer::prev_efb_format = PEControl::INVALID_FMT;
 unsigned int Renderer::efb_scale_numeratorX = 1;
 unsigned int Renderer::efb_scale_numeratorY = 1;
 unsigned int Renderer::efb_scale_denominatorX = 1;
@@ -89,7 +89,7 @@ Renderer::Renderer()
 Renderer::~Renderer()
 {
 	// invalidate previous efb format
-	prev_efb_format = (PEControl::PixelFormat)-1;
+	prev_efb_format = PEControl::INVALID_FMT;
 
 	efb_scale_numeratorX = efb_scale_numeratorY = efb_scale_denominatorX = efb_scale_denominatorY = 1;