Hi all and sorry for raising this topic from the land of the dead.
I was interested in the recent development on Master Everdrive X7 and its compatibility with japanese Master System (MK-2000) which I happened to acquire couple weeks ago. So my concerns are as follows:
1. How well does Master Everdrive X7 work with JP Master System with SMS2SG1000 cartridge adapter sold here:
https://www.aliexpress.com/item/SMS2SG1000-Sega-Master-System-U-S-Version-to-Sega-MARK-III-Japanese-Version-Adapter-SMS-Adapter/32664053050.html Earlier Krikzz mentioned that he had no issues except the in-game menu, but others have had some SD read errors. So I guess you have to have just the right SD card it to work properly? So basic stuff, but is there some incompatibility issues with certain games? Stlpaul responded earlier that there were problems in 2018 october. Are these issues still there?
2. What about compatibility with SMS gender adapter sold here:
https://www.smspower.org/Shop/GenderAdapter Has anyone made extensive use of the adapter with X7? Some people here said that in-game menu works but SD cards gets lots of errors? Would like to hear more especially about the games supporting FM sound.
3. Question for Krikzz: I guess this one is a distant pipe dream, but has there been any thoughts to make a japanese-friendly Mark III/SMS version of Master Everdrive (and possibly X5 version of it if the in-game menu doesn't work anyways) to eliminate all these adapter headaches. Just like there is a Famicom version of N8 Everdrive. That would be PERFECT!
4. If there isn't enough demand (as I suspect) for JP SMS/Mark III molded Everdrive, has anyone made 3D printed case for the SMS2SG1000 adapter to make the whole more nice looking and sturdy. Or maybe alternatively a case that could house the adapter AND the Master Everdrive X7 PCB without parts sticking out? I'm aware that D.Lo made a DIY case (detailed here:
https://nintendosegajapan.com/2015/03/13/creation-of-a-sega-mark-iii-everdrive-flash-cart/ ). Only problem that you have to sacrifice original game cart and it needs quite heavy modification to the PCBs and the case. And it still isn't ideal.
5. If it's no no to everything above, then what about an adapter that would be much lower profile than SMS2SG1000 so the original MARK III game case would fit much better? Just a thought.
6. And finally Krikzz: Should one just try to get old Master Everdrive instead X7 because of the incompatibility issues or is there possibly some OS update coming that would fix SD and in-game menu errors etc?
So yeah, many open questions as an happy owner of JP Master System.

And thanks for the reply in advance, I've been enjoying Mega Everdrive X5 and Everdrive GBA X5 immensly! Mega kudos to Krikzz!