Rairii,

downloaded a bunch of old world mac ROM dumps

the powermac G3 (v3) is the earliest to have an MS ARC-style COFF loader in its open firmware implementation

they were released nine months after MS announced they were abandoning PowerPC NT

edit because i got confused with the models. the blue and white G3 is of course the first new world powermac

wamwoowam,

@Rairii one of my powerbooks has openfirmware entries for coff-loader but also pe-loader? and it's from 2004, i have absolutely no idea what it could've been used for

Rairii,

@wamwoowam yeah, the pe-loader is the loader for COFFs with PE optional headers which is what link.exe /rom emits and is what veneer.exe, setupldr and osloader all are

wamwoowam,

@Rairii doesn't appear to work? i assume you already know this but i thought it was interesting to try

(to be clear i had no expectation this would run, i am somewhat surprised the loader itself doesn't function though)

Rairii,

@wamwoowam yeah, you might want to set little-endian back to false to avoid a brick here

also: setupldr.exe won't work, it was intended to load veneer which provides an arc firmware interface to load setupldr

wamwoowam,

@Rairii dont worry, i've not touched the little-endian parameter, so veneer is an ARC on OF "emulator" that... already exists in NT4?

Rairii,

@wamwoowam yes.

and: just trying to load a COFF with PE optional header in apple's OF implementation sets little-endian to true... same if you tried to load a ppcel ELF...

wamwoowam,

@Rairii didn't appear to for me, going to assume i got lucky and not poke further 😅

update it definitely did but i never cleanly shut down the machine afterwards so i just got very lucky

Rairii,

@wamwoowam i think so. it's supposed to run "force-reboot" after the "resetting to change configuration" print

"force-reboot" was only ever used for when setting little-endian on executable load

i'm not surprised it if got broken at some point and never fixed lol

wamwoowam,

@Rairii so then the question becomes if the little-endian? toggle actually does anything on a hardware level or just confuses the firmware?

Rairii,

@wamwoowam i think it does something on a hardware level (there's code in early OF to do lots of endianness swapping then set MSR_LE|MSR_ILE if something is set), that also happens to confuse the firmware, possibly third party graphics firmware in graphics card option ROMs

Rairii,

interestingly, "nt-hack" was added with the new-world blue and white G3.

as far as I can tell, "nt-hack" hooks the open firmware claim() function to cause all allocations less than 5000 bytes to fail (I think?)

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