[OpenBIOS] Apple's BootX

Mark Cave-Ayland mark.cave-ayland at ilande.co.uk
Thu Jan 25 22:52:50 CET 2018

On 25/01/18 15:01, Jd Lyons via OpenBIOS wrote:

> In an effort to figure out why qemu-system-ppc hangs at BootX when using 
> some emulated and KVM CPU’s, I suppose it would be good to enter some 
> breakpoints in the code.
> I found some BootX sources at:
> https://opensource.apple.com/tarballs/BootX/
> Tho I’m not sure what versions correspond to which release of OS X?
> And it’s not clear how to build them, tho I haven’t tried yet.
> I found some info on BootX as well as some idea how to do what I’m 
> looking to do:
> https://people.ffii.org/~zoobab/bh.udev.org/filez/apple/mac6100/BootX.pdf
> *There are few other useful debugging tech- niques. Setting "auto-boot?" 
> to false will cause the system to enter the OpenFirmware User In- 
> terface by default. Changing kFailToBoot to 0 in include.tproj/sl.h will 
> alter BootX’s default be- havior on error, so that it will return to 
> Open- Firmware. Finally, calling Enter(), will cause BootX to drop back 
> into the OpenFirmware User **Interface. This can be used as a break 
> point. The "dumpl" word will dump some memory, by en- tering the 
> address, then the length, then "dumpl". By calling printf in BootX 
> immediately before En- ter(), the address can be easily determined, and 
> the variable can then be examined and altered from OpenFirmware. Finally 
> typing the "go" command will resume BootX’s execution. *
> I noted when I boot from boot usb0/disk:3,\\:tbxi while holding 
> command+v BootX sends some info to the screen, seemingly via open 
> firware, while displaying the “Apple Logo” boot graphic. The info show 
> some of the boot process and what stage it’s loading” loading 
> mach_kernel’ “ loading the .mkext”
> It would be nice to get this output going via Open Bios, if anyone has 
> any idea how I might be able to do that?

Steve Troughton-Smith has previously custom built BootX from source in 
order to boot older versions of Rhapsody (see 
and https://github.com/steventroughtonsmith/BootX for more information).

If the instructions in the forum post don't give enough detail then it 
might be worth a direct email?



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