So I got it to work by updating the flashcart firmware to the beta version, but the SGB reads it as a DMG not a SGB, so only the DMG workers are active.
Hi, thanks for the report. This is good news that it does work on the SGB, although it's strange that it's detected as a DMG. The machine detection code is based on the memory value after bios boot, so the Flashcart firmware is maybe doing something here.
Could you please try again with the ROM file "gbcorp_full_nolink.gb " ? This version has the link-cable feature disabled for better compatibility with some Flashcart, maybe it'll help with yours too?
Hi again, sorry for all the messages, but I've just found this;
https://gbatemp.net/threads/nitro2k01s-sgb-enabler-for-ez-flash-jr.592961/
Basically it's a modified menu kernel that allow the EZ Flash Jr to work almost normally on a SGB.
If you try it, just to be safe, please backup your ezgb.dat from your SD before replacing it with the one from this archive.
Reading this, I think it's normal that the SGB is behaving like a DMG with the EZ Flash Jr, and it's due to the Flashcart not supporting the SGB and thus the game is not able to detect it. I hope this modified kernel will solve the issue