I know, tl;dr, but please bear with me here.

After googling almost everything I could think of, reading insanelymac and here; trying three different distros (old ToH disk I had lying around, iAtkos v2.0i, and iDeneb 10.5.5), The only progress I have to show for it so far is a nice stack of coasters. I've tried using AppleATIATA.kext, the SB700 kexts posted on insanelymac, injecting both into various install images, and unpacking the mkext from iDeneb and repacking with the chipset drivers that as far as I know is correct. Switching SATA modes is not an option, seeing as how the HP bios(es?) are the most stripped down things I've ever seen.

The computer in question is an HP tx2500 CTO, an AMD RM-70 processor, with CPUZ telling me that I'm running the 780G chipset with a SB700 southbridge, and ATI HD 3200 graphics (which isn't incredibly high on my priority list). I've tried everything I can possibly think of and right now I'm just looking for any other ideas anybody can possibly give.

With no boot options other than -v, I get still waiting for root device, platform= does nothing noticeable, and specifying the rd=disk0s1, causes a kernel panic with error type=0, divide error (or a nfs_boot_init error 4/6). I've tried -x, -f, -s, pretty much every letter of the alphabet, and I either get a panic, or a "still waiting". I know that the actual media I'm using is not corrupted, as I've used the same dvds to install on my girlfriend's ICHX dv2000 flawlessly. If anybody could give some expert advice or point me to other distros, it would be greatly appreciated, I'm almost pulling my hair out here.

(Device manager says my sata controller's dev id is 0x43911002, which I've added into AppleATIATA.kext)

edit: Currently it is running bios version F.05, but I've also tried F.08 and F.09 to no avail.