PSP coder Takka has recently updated his ISO Tool, a handy homebrew app that allows you to decrypt, convert and patch all the latest ISOs, making it compatible with your custom firmwared PSP. Tagged as version 1.91, the latest update includes several improvements and bug fixes.

Changelog (translated):

• [NEW] HBL at startup Fixed the error reappears PRX read (FW 5.51 or higher will have to come out)
• [NEW] HBL make changes when using the View menu,
• [BUG] HBL Fixed a freeze when using at the end (if you return to exit the menu HBL, HOME Back to the case of the XMB)
• [BUG] When you start "ms0: / test" was to remove fixed (remains of debugging)
• [BUG] EBOOT.OLD fixed conversion was not possible to
• [NEW] 5.50GEN-D3/D2 when patched in the farm system with "5.50GEN-pD ~" was to make the show
• [NEW] 5.50GEN-D2 system supports plug-ins