Mapper Megaram 512 issues

Thank you, that's what I was wondering. That clears a lot of confusion.

The first thing I did was partition the SD card with the CALL FDISK command it partitioned the SD card to less than 16 MB. It did this by default.

I've used your past posts to try to set this up. I put the command2 file and the Nextor.sys along with SR with the sofarun files.autoexec.bat as well. I never got the opportunity to enter any Nextor commands. Is there something I put into basic to be able to access Nextor? The only trace of it is it briefly showing slot info at the beggining after msx logo at startup. If I flip the switches, it will actually stay on this screen. I cannot put in any commands on this page.

I am at work on break trying to type this out on my phone as fast as I can. This is actually the second time I wrote this out, I somehow refreshed on accident!!

I apologize for the photos being so tiny. That's embarrassing. I have a lot to learn and I really appreciate the help.

@Pentarou isn't that a Windows Explorer feature? It hides extensions of files that are known... (very stupid if you ask me, but hey... it's Windows...)

I thought about Windows hiding the extensions, so I did check on my W10 machine and .COM was showing (Note: I NEVER use explorer so I though that was the default settings).

Well, anyway if filenames are correct, then another possible point of failure could be the firmware interfering with the cartridge.

But then you did partition it again, and this time with a larger size?
You didn't left it as FAT12, right?

Thank you very much, that's really good to know!

And thanks to everyone else as well. After rmuch frustration I decided to return this cartridge, and get another from a more reputable and responsive seller. Ill put the eBay Link up.