Based on a tip received earlier today, which we have independently verified, a copy of firmware 5.05 for PSP is included on UMD title Idol Master SP. There’s no changelog included and as such it is anyone’s guess as to what is new. Sources say the title fails to boot on the latest edition of M33 firmware, so this could very well be a compatibility update, which would explain why Sony has chosen not to release the firmware through usual channels.

Firmware updates have been released solely on UMD in the past. Hot Shots Golf 2 comes to mind, which included 3.96.

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