Ez flash junior: can’t use it on original GB (dmg-001):stuck on black bar logo

[Toff-niort]

Hi there!
I just bought an ez flash junior.
It works pretty well with :

• Unmodified GBA SP
• IPS screen GBA
• IPS screen GBC (except major bug in wario land 2: crash after each cutscenes, wario sprite glitched...)

but when it comes to the original gameboy (dmg-001) with ips4 V4 OSD screen mod, I only get the black bar logo ,then nothing. I use 1.5v batteries (brand new,energizer) . The machine works with traditional cartridges.

On EZ flash jr side, I’m using latest kernel and firmware (1.05). I've also tried to downgrade to v4 but the problem persists (and makes it unusable with my GBC).
I have tried to un plug/ replug many times, without success.

micro SD model :"16go micro sdhc" (formatted in fat32,32kb cluster, brand & model:sandisk Ultra A1)

Has anyone heard or dealt with the same issue,and if so, what did solve the problem?
could you help me troubleshoot this?
(sorry for my english, i hope it is
Thanks for your help

 

[Soundtoxin]

Hey, did you ever find a solution to this?