IMHO the 128KB BIOS from the Github (This one) is OK, but you should update the cart with the proper (FBL-UPD.COM) tool.
Do you have an FDD? Or can you get help from someone else whose MSX has a disk drive?
I'm going to buy a gotek you say? worth it
do you think FBL-records differently than an external recorder?
Maybe you could create a fdd .img, convert it to ROM file (dsk2rom), burn it into the flash cart (that is visible in one of the photos you posted), boot from the flash cart and use it to upgrade the SDMapper?
do you think FBL-records differently than an external recorder?
The tool will tell you if there is a problem with the mapper, the programmer won't help you if that is the problem.
I wouldn't know how to make this rom but yes it is possible for any rom on that board. she is multimapper
belavenuto tell me that if the msx does not have 256k ram only runs the dos1 would anyone there have this one of the 1?
He must have been wrong.
AFAIK the threshold is still 128KB.
But you can use the 512kb on the cartridge, so not a real problem.