Thanks for all the information you are providing. Despite my efforts I still am not able to boot my eMac G4 (Apple PowerMac6,4) by USB.
After reading your email I was able to see that with a USB stick inserted at boot a disk device indeed shows up in the device tree (visible by using the command "dev / ls"), but I am still not able to list its files by using the command "dir". By the way, the USB stick contains a dd'ed debian ISO image and it is possible to browse its files on a PowerMac G5 (PowerMac11,2). I think I am using the correct OF path, derived by looking at the device tree and by comparison with the working path on the G5. I can confirm it has OpenFirmware 3 as shown by the following command on OF: 0 > dev /openprom 0 > .properties name openprom device_type BootROM model OpenFirmware 3 relative-addressing supports-bootinfo boot-syntax 00000001 This is not the first time I bang my head against OF and USB boot. Eventually I ended up using NetBoot for a G3 and this G4 (which was not easy anyway especially on the G3). For what is worth, I think that a developer in need to test several CD images without burning them should consider investing in a FireWire HD. As far as I know booting from FireWire should be much easier, but I never tried it. Regards A. Il 30/04/19 21:56, Linux User #330250 ha scritto: > Am 30.04.19 um 12:54 schrieb John Paul Adrian Glaubitz: >> Hello! I have dug out one of my iBook G4s now so I can perform >> installer tests on the PowerMac target. While the machine has a >> built-in optical drive, I would avoid having to burn CDs for every >> installation test run (even when using CD-RWs), so I was wondering how >> well booting from USB sticks works on these machines. Does anyone have >> experience creating bootable USB media for PowerMacs to install >> Debian? Adrian > > Despite what others said, it should really work with every Macintosh > that has the NewWorld bootrom and thus at least Open Firmware 3.0, i.e. > starting with the iMac "Bondi" 1998 and the PowerBook G3 "Lombard" 1999. > > And, it's all already written down in a nice way.[1] Don't read on when > you are happy with this official guide. > > Or read this: > * http://hints.macworld.com/article.php?story=20060301112336384 > * https://lists.debian.org/debian-powerpc/2012/08/msg00042.html > * > https://sites.google.com/site/shawnhcorey/howto-boot-apple-powerpcs-from-a-usb-drive-in-open-firmware > > > The long read: I wanted to share my own experience as well... > > Apple did not provide an easy way, like holding a key for this kind of > boot selection. The possible keys are, a selection[2]: > * c – boot from CD-ROM (or any other /internal/ optical drive) > * d – forces boot from first hard disk drive (like it normally would anyway) > * n – network boot, looks for suitable BOOTP or TFTP network boot source > * r – (PowerBooks) resets stored screen size to internal default > * t – target disk mode > * mouse button held down – forces eject for media in internal optical drive > * option – shows Open Firmware boot selection > > Sadly, Apple decided to include FireWire in the automatic search for > bootable volumes but to leave out USB. The capability is there > nonetheless, only that there is no key for it to press and hold, like in > easy, quick and comfortable... > > The solution is to enter the Open Firmware (OF) command prompt by > holding Option + Command + O + F until you can read the Open Firmware > greeter on your monitor. Then you need to find the device and load the > boot file from there. In essence it is the manual way of what the other > options do for you automatically. > > > The syntax is like this: >> boot <dev>:<partition>,<file> > > > Examples for <dev>: > 1) /pci@f4000000/ata-6@d/disk@0 > 2) /pci@f2000000/mac-io@17/ata-3@20000/disk@0 > 3) bridge/ACARD,6280M@4/@2 > > Only, on most Macs there are aliases for this long and complicated > device paths. So, for example, all of those above could be just: > 1) hd (is set to the faster first HDD, should be the same as ultra0) > 2) cd (set to internal optical drive, e.g. ide0) > 3) ide0, ide1 (ATA bus) > 4) ultra0, ultra1 (UltraATA bus) > 5) usb0, usb1 > 6) ud0, ud1 – only on later PowerPC-Macs (like the Power Mac G5 or the > iMac G5, starting around 2003) > > So, to replicate the boot from CD-ROM (holding the "c" key on system > start-up) from the default partition (automatic), you can use the > following from the Open Firmware prompt: >> boot cd: > > To choose a specific partition, with a specific file as the initial > bootloader: >> boot cd:2,yaboot > > To use the blessed bootloader on a specific parition, in this example > partition 3 from the hard disk drive: >> boot hd:3,\\:tbxi > The <file> "\\:tbxi" is not a real file, instead OF will look for the > one file that is blessed on this partition, that is the one file that > has specific attributes to it. For Mac OS X this will be bootx, for > Linux normally yaboot or grub2. To my knowledge this only works on a > partition with HFS. > > > So, now we want to boot from USB. First you need to identify the path of > the USB device you want to boot from. Then you need to know the > partition number. And, maybe, also the name of the bootloader (or try > :tbxi). > > To find out what aliases your Mac already has defined, run the following: >> devalias > > To see the full device tree without aliases: >> dev / >> ls > > Other usefull commands in Open Firmware: > * lsdev > * .properties > * devalias, devalias <alias> <device-path> > * nvalias > * printenv, printenv <variable> > * set-env > * set-default <variable> > * set-defaults > * dir <devicepath or alias>: > * eject cd: > * mac-boot (will boot the standard) > * reset-nvram (same as Cmd+Opt+N+V) > * reset-all (will reboot) > > > If you somehow messed up your Open Firmware settings, you can always > reset/zap the NVRAM and the parameter memory (PRAM): > * Hold Cmd+Opt+P+R to zap the PRAM > * Hold Cmd+Opt+N+V to zap the NVRAM > hold the keys until you hear the startup chime. I always held the keys > until I heard the chime /again/ and /again/ 3 times in total. It's said > that it has to be done this way. > > > I think that on my Power Mac G5 (PowerMac11,2) from 2005 I was able to > boot from the USB drive with: >> boot ht@0,f2000000/pci@4/usb@b/disk@2:2,\\:tbxi > or >> boot ht@0/pci@4/usb@b/disk@2:2,\install\yaboot > I found some notes, this must have been last year or so. > > > I just tried 2019-04-24/debian-10.0-powerpc-NETINST-1.iso on my iBook G3 > (original Clamshell, 1999) and it did not boot with: >> boot usb0/disk@1:2,\\:tbxi > I got "can't OPEN: cd:,\install\yaboot" > I then tried >> boot usb0/disk@1:2,\install\yaboot > and this worked. > > BTW, in yaboot I get this warning: >> WARNING: Bootstrap partition type is wrong: "Apple_HFS" >> type should be: "Apple_Bootstrap" > > > One more note on the USB boot front: I use one of those sticks that can > be write-protected by a physical slider on the side of the stick. WHEN > the stick is read-only, OF is unable to access it properly. Not even the > dir command works. Without write-protection everything works fine with > the same stick/same data on it. > > > For what it's worth, USB booting on a Power Mac is alwayy trial and > error. Write down what works. I heard that it should be possible to > define a new devalias somehow... Also, setting boot-device in nvram[4] > could make the boot selection permanent (until the PRAM is zapped or the > battery dies). > >> setenv boot-device usb0/disk@1:2,\install\yaboot > Only, in the case of an external USB pen drive, I would advice against > it...But I can confirm that this also works! >> mac-boot > will then boot from the USB pen drive, as will every restart as long as > the stick remains plugged in. > > > Cheers, > Linux User #330250 > > > > [1]https://www.debian.org/releases/sarge/powerpc/ch05s01.html.en > [2]https://whircat.centosprime.com/startup-keys-boot-options/ > [3]https://cdimage.debian.org/cdimage/ports/2019-04-24/debian-10.0-powerpc-NETINST-1.iso > [4]http://www.macfreek.nl/memory/Open_Firmware >
