Dewit has updated PocketNES once again. It’s considered a buggy alpha, so use it with cautation.

Fixed bugs
* Less crashes when using compressed roms

New Features
* Rewrote the Background Tile update system, so now it delays changes to the nametables until the next frame, so that the graphics synchronized properly. No more disappearing ? blocks in Super Mario Bros. (Punchout and 4-screen mirroring is currently broken)

Optimizations
* Games run much faster in this version
* Replaced some memory filling/copying loops with faster multi-register writing code
* Very heavy optimizations to PPU status reads, almost makes PPU hack unnecessary
* Now stores fixed PRG bank inside Fast Video RAM instead of slow cartridge slot, huge speedups for this reason

What’s broken:
* PPU Hack does nothing right now
* PUNCHOUT is broken
* TQROM and Mapper 74 are broken
* 4 screen mirroring is broken
* Savestates are buggy
* Don’t try to use the cheat finder right now.

Internal changes which only make sense if you’re the developer
* Moved some code out of IWRAM, including the multiplayer link code. (it’s still there, just no longer wasting fast memory)
* Different timeout system

http://www.dwedit.org/dwedit_board/viewtopic.php?id=345