I tried USB or CD method but have the same message error : Firmware Upgrade of SDSSDH2128G failed…
It seems there may be an issue writing to the area where the FW is stored. It would be a long shot but if you have another PC you could try the update from there. If it fails as well the SSD would need to be replaced.
The same situation with another computer. Its SanDisk fault
I had a similar problem with one of my 256GB Ultra Plus SSDs. Right after a firmware upgrade, my drive was detected by Windows as only 50GB, and without any volume!
Although I had made a backup of my data before the upgrade, I was not happy about my drive not functioning properly. It was all the more frustrating that DashBoard had nothing wrong to report about my drive, except the size. Looking at the details section of DashBoard, and comparing with another 256GB Ultra Plus, I noticed that the only difference (except the serial number) was a much lower “Max LBA” value.
In despair, I searched for a way to modify that “Max LBA” value, and discovered the HDAT2 utility. I tried its “Set Max Address” feature, rebooted, and… Tadaaa, my volume was back with all my data! And of course, the reported size was back to normal. Since then, that drive has been flawless.