Mechapwn not working on my Ps2 NTSCJ 50000 Midnight Blue

Need the community's aid for this one. Recently bought a Japanese Ps2. Wanted to start collecting ps2 classics so I tried installing mechapwn for the first time. I was under the understanding that with 5k onwards consoles mechapwn can be installed with retail - DEX converting it to a debug system so its stops honoring regions locks for PS2 games. Downloaded Mechapwn 3.0 RC4

I followed the steps to the letter. I got a cross region FMCB ver 1.966 unplugged the cord as the steps instructed. Once it was all done I removed the FMCB and usb stick and even changed the system language to english.. so far so good. Until I noticed the ps2 version still said scph-50000 isn't this supposed to change to DTL -XXX or something? anyway I tried loading PAL GTA got nothing...said no data. tried some other copies of other random ntsc UC games still nothing. jap games still work tho...what went wrong? plz help.