SiI3112 is a SATA chip with firmware and drivers available for MacOS. Note that it is officially spelled SiI, not SiL, but many online references spell it SiL.
PC versions of the cards can be flashed with the Mac firmware. This makes it possible to boot from them.
? Do the cards work as non-boot drives without flashing?
Two companies made SATA PCI cards for the Mac. WiebeTech and FirmTek. The WiebeTech firmware fits in 64KB and only works on MacOS X. The FirmTek firmware is bigger than 128KB and works on MacOS 7.6.1 through MacOS X. The Sonnet Tempo SATA uses the FirmTek firmware.
SiI
FirmTek white-listed flash chips: PMC Pm39LV040, Macronix MX29LV040, Am29LV040B
Replacing the flash chip:
hot air 260C for 30 seconds and it just slides off… you have to be a little careful of the caps
http://www.firmtek.com/download/SeriTek1S2_513.zip
https://68kmla.org/forums/index.php?/topic/13557-sil3112-flashing-sata/page-2#entry207493