Notaz has released a new version of Picodrive for the GP2x.

Author release notes:

After nearly 4 months I finally updated my Genesis/MegaDrive/SagaCD/MegaCD emu. This is a maintenance release, with fixes for various issues reported over time.

ketchupgun persuaded me to change menu graphics a bit, so now it has some skinning support. Nothing new on the emulation front

Changes:

Updated Cyclone core to 0.0088.
Added A r k’s usbjoy fix.
Added “perfect vsync” option, which adjusts GP2X LCD refresh rate and syncs emulation to it to eliminate tearing and ensure smoothest scrolling possible.
Added an option to use A_SN’s camma curve for gamma correction (improves dark and bright color display for mk2s).
Sometimes stray sounds were played after loading a savestate. Fixed.
Fixed a problem where >6MB mp3s were corrupted in memory (sound glitches in Snatcher).
PD no longer overwrites video player code in memory, video player now can be used after exiting PicoDrive.
Fixed a bug which was causing Sonic 3 code to deadlock in some rare conditions if “accurate timing” was not enabled.
Fixed support for large hacked ROMs like “Ultimate Mortal Kombat Trilogy”. Upto 10MB hacked ROMs are supported now.
Config profiles added (press left/right when saving config).
Changed key configuration behavior to the one from gpfce (should be more intuitive).
Added some skinning capabilities to the menu system with default skin by ketchupgun. Delete skin directory if you want old behaviour.
Some other little tweaks I forgot about.

http://notaz.gp2x.de/releases/PicoDrive/PicoDrive_133.zip