According to MacTracker, the the Beige G3 series originally shipped with Mac OS 8. Thus, i would imagine it is not officially supported. Short of that, the last time i have personally seen system 7 is on my old 'pizza box' mac. It may be possible to install that system, with the enabler, on something like an 8600, then move the drive over to the beige. I will say that, in my experience with my beige G3 minitower (which i have had since 1997, and recently rebuilt), they can be a bit picky about booting oddball OSes.

I realise i've not given you any hard info, but, the long and short of it is; i have no idea, but it might work. try it.
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