Stuck at flashing [ ? ] with a brain fart!

[l008com]

PowerMac 7300 with a hard drive partitioned into many slices. So it can run 7.5, 7.6, 8.1 and more.
In startup disk control panel, I picked a volume that is actually blank. I rebooted and now I'm getting the blinking question mark and I cannot remember how, on these old systems, you change the boot disk setting! PRAM reset didn't help. I don't have any floppies so I can't do a startup disk. ACK!

 

[l008com]

I was able to scrounge up a macos 8 drive setup bootable cd rom and that saved me. Well I assume it saved me as it's booting right now.
Confirmed, it saved me. I didn't even have to choose a disk. I just put it in, held C, and instead of booting off the CD ROM, it just booted off my 7.5.5 volume, which is fine and got the job done.

 

[LaPorta]

In the future, try Command-Option-Shift-Delete-SCSI ID number if you have a physical drive. Helps as well.

 

[l008com]

The physical drive is SATA connected to a PCI IDE card. Although the system still sees that as SCSI so maybe that would still work.

 

[joevt]

How does Startup Disk control panel let you pick a volume that is blank?

A couple things you can examine before and after changing the startup disk:
A dump of the partition map (with partition flags). My fork of DingusPPC outputs this info when you connect a disk image. Or you can run my dumpvols.sh script in Mac OS X which dumps info from each partition as well.
https://gist.github.com/joevt/a99e3af71343d8242e0078ab4af39b6c
Change the startup disk then shutdown. Transfer the drive to a modern Mac to examine the changes.

A dump of the nvram and pram using my DumpNameRegistry app.
https://68kmla.org/bb/threads/skipping-the-startup-memory-test.50699/post-570896
Run the app before and after changing the startup disk and compare the nvram contents. This might not show any changes if the NVRAM/PRAM is not written until shutdown. In that case you may need to restart to see the changes. But if you can't boot then that won't work. Best way to examine changes to NVRAM/PRAM is to restart into Open Firmware and dump the NVRAM from there over serial port to another PC.

If you can learn how the startup disk is chosen, then a program can be made to change that in Open Firmware.

 

[l008com]

How does Startup Disk control panel let you pick a volume that is blank?

Yeah, thats a good question. But it did. I think I was in 7.5.5 when it let me pick the blank drive. I assumed it had an OS on it since it let me pick it.

 

[robin-fo]

It should still automatically boot from another drive or partition, though…

 

[l008com]

Yeah it was weird. Thats classic macos for ya.

 

[LaPorta]

7.5.5 will let you select anything. That was corrected I believe from 7.6 on.