More SD card fun

Am Freitag, 27. Mai 2016 23:44:03 UTC+2 schrieb Les Cargill:

We had similar cases. My theory is as follows: the SD-card standard includes some larger register spaces that contain information such as supply voltage, vendor, speed, etc. To save cost, the vendors use the same flash array to store that info and reserve a few sectors when they create the file system. When you reformat the card and use those sectors for the partition table or the new file system, then the card becomes unusable. I tried to copy the lower sectors back in such a case but it did not help, probably the driver was missing already too much information. It might help to skip the first sectors when creating partitions. Andreas