I have a failed 750Gb AS drive that is one of the ones with the Thai Firmware SD15, in checking that out I find I also have 4 other drives but all ES 2 drives that are also effected and two ES ones that are OK.
After paying a bit over the odds for the ES drives I would never have expected this.
Will try updating the Bios on the ES drives
I have ordered an identical model AS drive and hopefully I can switch the PCB over and have it run long enough to get the data off it. For the cost of an identical HDD should still be cheaper than a Data Recovery company provided it works