Cannot change all sprite properties in VRAM

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Open BizHawk 1.9.2.
2. Launch "Disney's Aladdin (U) [!]" (Genesis).
3. Start the game. When you can control Aladdin, press Start to pause the game. 
While paused, the VRAM is not modified by the game, so it is easier to 
experiment with it and reproduce this bug.
4. Open the Hex Editor, set the domain to VRAM, enable Big Endian, go to 
address 0xF400. That address contains the Sprite Table, as described here: 
http://md.squee.co/wiki/VDP#Sprites
5. Try changing the 0xF406 value (by pressing + and -). It corresponds to the X 
position of the sprite. It works. Try changing the 0xF404, which corresponds to 
the sprite priority, palette, hor/vert flipping, and the pattern data. It also 
works.
6. Try changing 0xF402 bits 8 to 11 (i.e. this nibble: 0x#_##). It should 
change the sprite dimensions. It does not work. Try changing 0xF400, it should 
change the Y position. It does not work.

What is the expected output? What do you see instead?
The step 6 should work, just like step 5. However, step 5 works, while step 6 
doesn't.

Related discussion: http://tasvideos.org/forum/viewtopic.php?t=16495

Original issue reported on code.google.com by denilsonsa on 7 Mar 2015 at 9:21