S2 Special Stage problem (I guess it's RAM)

Hi.

I dicovered very weird problem with special stage in my hack. In the last stage, in last section, few segments arn't loaded, but instead the last segment is looped and looped over again causing the player to being stuck and reset the game. I discovered too that it's related with my Knuckles + Tails S art. I needed to extend "SSRAM_ArtNem_SpecialSonicAndTails" variable from 353*20 (S+T art tiles) to 38A*20 (K+T tiles number) because it was glitched when playing as Knux (random sprites everywhere). I guess that this caused the problem, because when I changed back to 353, it worked perfectly. SO my question is: how I can extend "SSRAM_ArtNem_SpecialSonicAndTails" so rest of Special Stage won't be broken? I'm almost sure that i need to free up somehow 6E0 ((38A-353)*20) bytes but I absolutely don't have idea how.

Thanks in advice.

 

Well, you could load the collision arrays from ROM.. But since only $600 bytes are freed, that's out of luck.

http://sonicresearch.org/forums/index.php?showtopic=4184

 

The Special Stage loads:

• Character art into 68k RAM at 0000.
• Perspective data into 68k RAM at 6A60.
• Layout data into 68k RAM at 855C.
• Object Layout data into 68k RAM at 8778.

The art size being 353 x 20 = 6A60. The only way you're going to fit your new sized art into RAM, is to move the "Perspective", layout, and/or object layout data; further down, or somewhere else.
An alternative method, is to have the art data uncompressed in the ROM, and performing the DMA transfers directly from the ROM space into VRAM, rather than from RAM into VRAM. Sonic Team did the latter more than likely because of SEGA's request to keep the ROM size to a minimum where possible.