Cybdyn Systems just released a new menu (Version 2.6, build 5) and ARM (Firmware 2.6.1) updates for the PSIO. Matt, one of the PSIO developers, stated on the official forums that the new updates will fix the problems that some users encountered after installing the recent updates (Version 2.6, build 4).
Some bug fixes were done and that fixed a handful of games, here’s the list as stated by Matt:
[Menu System Changes]
– [Bug Fix] The intro video now plays properly and returns properly.
– [Bug Fix] Fixed analog controller mode switching for all versions of “Ace Combat 2”.
– [Bug Fix] Fastboot updated to V2.1. Fixes “Soul Blade” crashing on stage selection.
[ARM Firmware Changes]
– Fixed the intro desync issue with “Parappa the Rapper”.
– Set seek delay adjusted which fixes “DOOM” and “Final DOOM”.
– Adjusted the sector location offset which fixes “Blasto”.
Unfortunately, reports are coming in that Cybdyn is now requiring that a serial number and order number is entered in their website in order to download the update. I’m not sure why the update process seems to be getting harder, but hopefully Cybdyn will comment.
Official update statement: http://www.cybdyn-systems.com.au/forum/viewtopic.php?f=80&t=1143&p=14659#p14659