PlayStation Development Network

Hi
I buyed a chip psnee at tiny 45, the seller say Its programmed multiregion, but installed on my jap pu20 (the install Is fine) boots only japanese burned games. So the region hack isnt working fine. What Is the problem here? Is not a multiregion program? I think he programmed It wrong, but i wait confirm from someone here.
I can reprogam It using a esp8266? There Is a detailed guide for It?

understood:

"Later Japanese systems, starting some time during the SCPH-3000’s, and everything after, won’t be able to play non-NTSC-J games with a PsNee. There is additional region locking in the BIOS. You can either swap the BIOS chip with one out of an American console, or patch your backups to be NTSC-J region."

there is no way to fix it?
other old chip like mm3 will work on a jap ps1 with pal games or not like psnee?

console is scph7000