I used the USB.CFG method to transfer the iso to dev_hdd0/ps2iso, the game is Persona 4.
I installed ReactPSn, made "aa" and changed it by ReactPSN, installed PS2 classic place holder and ready to install it from the ps2 retro tab on mMCM, and getting this error code.

Error text (in case of Imagebam errored) :
This operation is not allowed
ISO TYPE : 14
ISO PATH (I) : [/dev_hdd0/PS2ISO/Persona 4.iso]
ISO PATH (O) :[/dev_hdd0/PS2ISO/Persona 4.iso]
ISO SEGS : 1
ERROR : 80010003 (ENOSYS)
I installed ReactPSn, made "aa" and changed it by ReactPSN, installed PS2 classic place holder and ready to install it from the ps2 retro tab on mMCM, and getting this error code.

Error text (in case of Imagebam errored) :
This operation is not allowed
ISO TYPE : 14
ISO PATH (I) : [/dev_hdd0/PS2ISO/Persona 4.iso]
ISO PATH (O) :[/dev_hdd0/PS2ISO/Persona 4.iso]
ISO SEGS : 1
ERROR : 80010003 (ENOSYS)