The VT6421A is a PATA/SATA PCI controller that can be found on various cheap PCI cards. Currently there is a datasheet hosted at .
There exists a patch for flashrom that makes it possible to access the attached flash chip, but it has problems with some cards. They seem to need an offset added to the chip address for unknown reasons.
Cards found in the wild
|Eminent||EM2001||0910CD||Taiwan||Pm49FL004||512k||0xfff80000 = 0xffffffff - size + 1 (aka phys_addr)||Szabolcs|
- The revision consists of two characters that are printed below the "VT6421A" string on the chip prefixed by 4 numbers that encode the production year and week. The country is noted right of the revision.