In some other replies to questions you've asked, the question of
Firmware Update for iMac G3 models may have been covered.
A command-line or bootROM startup to see the underlying code
is a different matter with the old hardware, so some unix code
would not be applicable, compared to a later hardware model.
This article for that vintage hardware has important details about
Firmware Update and it must be installed correctly as indicated.
If the Firmware has not been updated with the computer running
a non-OS X version as indicated, of the correct vintage Mac OS,
then it may work. There is no third party method to make this work
if you want to run the supported Mac software on it. Hardware may
be damaged as a result of attempting to run OS X w/o Firmware U/D.
The older Mac OS 9.x as stated per vintage hardware method is a
correct path to install the firmware. This one is the only one, if you
have the listed iMac G3. Older model iMac G3s use a different one.
•iMac G3 (slot-load) - for info only - download link inop:
Install iMac Firmware 4.1.9 Before Mac OS X 10.2 or later
http://support.apple.com/kb/ht3036
•iMac Firmware Update 4.1.9: Information and Download
http://support.apple.com/kb/DL1283
•Mac OS X: Available firmware updates
http://support.apple.com/kb/HT1395
Not sure if any of these will help if you did something not in actual
instructions given in support articles on how to update this firmware.
There had been other articles, whose page URLs now only go to
the main current Support page (vintage pages were moved) and so
other ideas on how to make a old Mac work if the Firmware Update
failed to work, or if it produced an odd defect, aren't there. A general
search online for those may take considerable effort at this late date.
These models likely are too old to access much, lacking more recent
'open firmware' kind of single-user 'command line' access. I don't
recall ever having tried or needing to with various older models.
And I've owned a few iMac/Mac G3 models, & updated firmware.
Seems to me one of your other questions with a reply covered as
much as you'd normally need to access the BootRom info at a
level below a GUI system; you should try to stay in one thread.
Sorry to not have an exact answer.
Good luck!😐
