Well my question is regarding that picture exactly . How do i differentiate a S19 that should be on the May 2021 firmware vs one that should have the Oct 15 . The reason i ask if because when u SD recovery a S19 with issues , the firmware shown is the recovery one which is the same for both versions .
So unless you marked down what Firmware u had prior to SD flashing , you'd have no idea but i'm thinking there must be a way to tell no ?
Currently, there is no other SD card firmware for s19 they only have one image even on BraiinsOS, ASIC.to, and Awesomeminer they do have SD card firmware but it won't flash directly to the nand.
How about flashing it two times?
And what exactly is the issue you currently experience?
If the firmware from Bitmain does no solve your case you can use other firmware available from what I mentioned above it won't flash to nand but it will boot directly from your SD card. So you need to keep the SD card plugged.
Or try to contact Bitmain and maybe they do have another SD card image that can totally clear the Nand program.