[ISSUE]: SCPH 50004 won't read Japanese discs

[AnkiWazabi]

Checks

• I provided nvram backup file
• I provided sticker photo

Console model

SCPH-50004

Describe the issue

Hi, after installing MechaPwn et selecting my model/region, I still can't boot my Japanese games.
My European games still boots fine.
I tried selecting SCPH 50004 EU and 5000X JP, and for EU it asks me to insert a correct PS2 or PS1 disc, for JP it goes back to the memory card menu.

Here is the nvram backup file : https://we.tl/t-LcE9j9f5jt (will last for a week, tell me if you need it again later)