diff --git a/GL/framebuffer.c b/GL/framebuffer.c
index 663a9c7..c011952 100644
--- a/GL/framebuffer.c
+++ b/GL/framebuffer.c
@@ -1,4 +1,6 @@
 #include <stdio.h>
+#include <assert.h>
+
 #include "private.h"
 #include "../include/glkos.h"
 #include "../include/glext.h"
@@ -156,37 +158,37 @@ GLboolean _glCalculateAverageTexel(const GLubyte* src, const GLuint srcWidth, co
     if((pvrFormat & PVR_TXRFMT_ARGB1555) == PVR_TXRFMT_ARGB1555) {
         a = A1555(*s1) + A1555(*s2) + A1555(*s3) + A1555(*s4);
         r = R1555(*s1) + R1555(*s2) + R1555(*s3) + R1555(*s4);
-        g = G1555(*s1) + R1555(*s2) + R1555(*s3) + R1555(*s4);
-        b = B1555(*s1) + R1555(*s2) + R1555(*s3) + R1555(*s4);
+        g = G1555(*s1) + G1555(*s2) + G1555(*s3) + G1555(*s4);
+        b = B1555(*s1) + B1555(*s2) + B1555(*s3) + B1555(*s4);
 
         a /= 4;
         r /= 4;
         g /= 4;
         b /= 4;
 
-        *d1 = (a << 15 | r << 10 | g << 5 | b);
+        *d1 = PACK_ARGB1555(a, r, g, b);
     } else if((pvrFormat & PVR_TXRFMT_ARGB4444) == PVR_TXRFMT_ARGB4444) {
         a = A4444(*s1) + A4444(*s2) + A4444(*s3) + A4444(*s4);
         r = R4444(*s1) + R4444(*s2) + R4444(*s3) + R4444(*s4);
-        g = G4444(*s1) + R4444(*s2) + R4444(*s3) + R4444(*s4);
-        b = B4444(*s1) + R4444(*s2) + R4444(*s3) + R4444(*s4);
+        g = G4444(*s1) + G4444(*s2) + G4444(*s3) + G4444(*s4);
+        b = B4444(*s1) + B4444(*s2) + B4444(*s3) + B4444(*s4);
 
         a /= 4;
         r /= 4;
         g /= 4;
         b /= 4;
 
-        *d1 = (a << 12 | r << 8 | g << 4 | b);
-    } else if((pvrFormat & PVR_TXRFMT_RGB565) == PVR_TXRFMT_ARGB4444) {
+        *d1 = PACK_ARGB4444(a, r, g, b);
+    } else if((pvrFormat & PVR_TXRFMT_RGB565) == PVR_TXRFMT_RGB565) {
         r = R565(*s1) + R565(*s2) + R565(*s3) + R565(*s4);
-        g = G565(*s1) + R565(*s2) + R565(*s3) + R565(*s4);
-        b = B565(*s1) + R565(*s2) + R565(*s3) + R565(*s4);
+        g = G565(*s1) + G565(*s2) + G565(*s3) + G565(*s4);
+        b = B565(*s1) + B565(*s2) + B565(*s3) + B565(*s4);
 
         r /= 4;
         g /= 4;
         b /= 4;
 
-        *d1 = (r << 11 | g << 5 | b);
+        *d1 = PACK_RGB565(r, g, b);
     } else {
         fprintf(stderr, "ERROR: Unsupported PVR format for mipmap generation");
         _glKosThrowError(GL_INVALID_OPERATION, __func__);
@@ -239,7 +241,6 @@ void APIENTRY glGenerateMipmapEXT(GLenum target) {
         GLuint thisWidth = (prevWidth > 1) ? prevWidth / 2 : 1;
         GLuint thisHeight = (prevHeight > 1) ? prevHeight / 2 : 1;
 
-        /* Do the minification */
         for(sx = 0, dx = 0; sx < prevWidth; sx += 2, dx += 1) {
             for(sy = 0, dy = 0; sy < prevHeight; sy += 2, dy += 1) {
                 GLubyte* srcTexel = &prevData[
@@ -266,6 +267,8 @@ void APIENTRY glGenerateMipmapEXT(GLenum target) {
         prevWidth = thisWidth;
         prevHeight = thisHeight;
     }
+
+    assert(_glIsMipmapComplete(tex));
 }
 
 GLenum APIENTRY glCheckFramebufferStatusEXT(GLenum target) {
diff --git a/GL/private.h b/GL/private.h
index c33a1a1..ed1ac9a 100644
--- a/GL/private.h
+++ b/GL/private.h
@@ -15,6 +15,14 @@
 #define FASTCPY(dst, src, bytes) \
     (bytes % 32 == 0) ? sq_cpy(dst, src, bytes) : memcpy(dst, src, bytes);
 
+#define _PACK4(v) ((v * 0xF) / 0xFF)
+#define PACK_ARGB4444(a,r,g,b) (_PACK4(a) << 12) | (_PACK4(r) << 8) | (_PACK4(g) << 4) | (_PACK4(b))
+#define PACK_ARGB8888(a,r,g,b) ( ((a & 0xFF) << 24) | ((r & 0xFF) << 16) | ((g & 0xFF) << 8) | (b & 0xFF) )
+#define PACK_ARGB1555(a,r,g, b) \
+    (a > 0 | (r >> 3) << 10 | (g >> 3) << 5 | (b >> 3))
+#define PACK_RGB565(r,g,b) \
+    ((r >> 3) << 15 | (g >> 2) << 11 | b >> 3)
+
 #define TRACE_ENABLED 0
 #define TRACE() if(TRACE_ENABLED) {fprintf(stderr, "%s\n", __func__);}
 
diff --git a/GL/texture.c b/GL/texture.c
index 23413b3..39c01e9 100644
--- a/GL/texture.c
+++ b/GL/texture.c
@@ -23,12 +23,6 @@ static TexturePalette* SHARED_PALETTES[4] = {NULL, NULL, NULL, NULL};
 
 static GLuint _determinePVRFormat(GLint internalFormat, GLenum type);
 
-#define PACK_ARGB8888(a,r,g,b) ( ((a & 0xFF) << 24) | ((r & 0xFF) << 16) | ((g & 0xFF) << 8) | (b & 0xFF) )
-
-
-#define _PACK4(v) ((v * 0xF) / 0xFF)
-#define PACK_ARGB4444(a,r,g,b) (_PACK4(a) << 12) | (_PACK4(r) << 8) | (_PACK4(g) << 4) | (_PACK4(b))
-
 static GLboolean BANKS_USED[4];  // Each time a 256 colour bank is used, this is set to true
 static GLboolean SUBBANKS_USED[4][16]; // 4 counts of the used 16 colour banks within the 256 ones
 static GLenum INTERNAL_PALETTE_FORMAT = GL_RGBA4;
@@ -172,37 +166,48 @@ static GLuint _glGetMipmapDataOffset(TextureObject* obj, GLuint level) {
 
     if(obj->isPaletted){
         switch(size >> level) {
+            case 1024:
+            offset = 0x15556;
+            break;
+            case 512:
+            offset = 0x05556;
+            break;
             case 256:
-            offset = 0x05558;
+            offset = 0x01556;
             break;
             case 128:
-            offset = 0x01558;
+            offset = 0x00556;
             break;
             case 64:
-            offset = 0x00558;
+            offset = 0x00156;
             break;
             case 32:
-            offset = 0x00158;
+            offset = 0x00056;
             break;
             case 16:
-            offset = 0x00058;
+            offset = 0x00016;
             break;
             case 8:
-            offset = 0x00018;
+            offset = 0x00006;
             break;
             case 4:
-            offset = 0x00008;
+            offset = 0x00002;
             break;
             case 2:
-            offset = 0x00004;
+            offset = 0x00001;
             break;
             case 1:
-            case 0:
             offset = 0x00000;
             break;
         }
     } else {
         switch(size >> level) {
+            case 1024:
+            offset = 0xAAAB0;
+            break;
+            case 512:
+            offset = 0x2AAB0;
+            break;
             case 256:
             offset = 0x0AAB0;
             break;
@@ -248,7 +253,7 @@ static GLuint _glGetMipmapDataSize(TextureObject* obj) {
     /* The mipmap data size is the offset + the size of the
      * image */
 
-    GLuint imageSize = obj->width * obj->height * obj->dataStride;
+    GLuint imageSize = obj->baseDataSize;
     GLuint offset = _glGetMipmapDataOffset(obj, 0);
 
     return imageSize + offset;