PCIE-SSD Option ROM AHCI help

[vin047]

I have a Kingston HyperX Predator PCIE-SSD (model: SHPM2280P2H) matched with an X58 motherboard (legacy bios). The card has a Marvell 88SS9293 controller with an Option ROM which allows it to be detected on my motherboard as a bootable drive - listed as "IDE: Kingston SHPM". As my BIOS is non-UEFI, I assume the Option ROM presents it in IDE mode instead of AHCI.
 
I use Clover legacy with BiosBlockIO to get around this, and it works well - Clover detects my drive and allows me to install macOS onto it and use it as a boot drive. macOS detects the drive correctly as a SATA AHCI drive. I guess Clover correctly detects (configures?) the Option ROM into AHCI mode and presents it as such to macOS - getting full speed read Read/Write performance. All is well.
 
Except waking from sleep. When waking from sleep, depending on clover config options + dsdt, I either get an immediate reboot or hang on black screen that requires hard reset. I eventually realised that nothing after entering sleep mode is recorded in the logs, its completely empty until next boot up. This makes me think that on resume from sleep, macOS isn't seeing the drive anymore (hence can't even write to logs). My assumption here is that the Option ROM is presenting/configuring the card in IDE mode, which is not what macOS is expecting.
 
This post describes the problem: 

 

and also has a solution: in dsdt, simply write the correct values to 0x40, 0x41, 0x42 (which must be the BAR0 register?) to configure Option ROM to use AHCI mode. But I have no idea what address BAR0 is on the Marvell 88SS9293 - there appears to be no documentation whatsoever on this controller available online!
 
I managed to dump the ROM using Linux sysfs, but don't have the skills to disassemble/decipher the binary to find the correct addresses. Anyone with such experience able to help?? I've attached the ROM dump and lspci output.
 
Thanks in advance!

rom.bin

lspci_output.txt