diff --git a/GPU/GLES/StencilBuffer.cpp b/GPU/GLES/StencilBuffer.cpp
index d6d357ad3d..bba59b2549 100644
--- a/GPU/GLES/StencilBuffer.cpp
+++ b/GPU/GLES/StencilBuffer.cpp
@@ -51,10 +51,10 @@ static const char *stencil_vs =
 "}\n";
 
 static u8 StencilBits5551(const u8 *ptr8, u32 numPixels) {
-	const u16 *ptr = (const u16 *)ptr8;
+	const u32 *ptr = (const u32 *)ptr8;
 
-	for (u32 i = 0; i < numPixels; ++i) {
-		if (ptr[i] & 0x8000) {
+	for (u32 i = 0; i < numPixels / 2; ++i) {
+		if (ptr[i] & 0x80008000) {
 			return 1;
 		}
 	}
@@ -63,25 +63,25 @@ static u8 StencilBits5551(const u8 *ptr8, u32 numPixels) {
 }
 
 static u8 StencilBits4444(const u8 *ptr8, u32 numPixels) {
-	const u16 *ptr = (const u16 *)ptr8;
-	u8 bits = 0;
+	const u32 *ptr = (const u32 *)ptr8;
+	u32 bits = 0;
 
-	for (u32 i = 0; i < numPixels; ++i) {
-		bits |= ptr[i] >> 12;
+	for (u32 i = 0; i < numPixels / 2; ++i) {
+		bits |= ptr[i];
 	}
 
-	return bits;
+	return ((bits >> 12) & 0xF) | (bits >> 28);
 }
 
 static u8 StencilBits8888(const u8 *ptr8, u32 numPixels) {
 	const u32 *ptr = (const u32 *)ptr8;
-	u8 bits = 0;
+	u32 bits = 0;
 
 	for (u32 i = 0; i < numPixels; ++i) {
-		bits |= ptr[i] >> 24;
+		bits |= ptr[i];
 	}
 
-	return bits;
+	return bits >> 24;
 }
 
 bool FramebufferManager::NotifyStencilUpload(u32 addr, int size, bool skipZero) {