diff --git a/src/hardware/hw_cache.c b/src/hardware/hw_cache.c
index dbeecb1b2..85a7fb4bb 100644
--- a/src/hardware/hw_cache.c
+++ b/src/hardware/hw_cache.c
@@ -302,7 +302,7 @@ static void HWR_DrawPatchInCache(GLMipmap_t *mipmap,
 	blockmodulo = pblockwidth*bpp;
 
 	// Draw each column to the block cache
-	*block = mipmap->data;
+	*block = (UINT8)mipmap->data;
 
 	for (int x = 0; x < pwidth; x++, block += bpp, xfrac += xfracstep)
 	{