Hi: I had a similar issue with writing the BIOS setting to USB, but slightly different than what you describe (its happened twice so far):
I boot into BIOS using F10, and go to Replicated Setup. It asked me to "Select a Drive" -- the only option presented was "USB." I accepted. It said "Saving Configuration." After a long delay, it responded back:
"Error. Removaable Media is bad or missing. Press any key to continue."
It seems to have seen the USB drive, as it presented the option to write to it. But then could not write to it after all.
Any suggesttions?
(I'm not clear on the need to save the settings to a text file. It seems like a good idea to have the settings saved, and you memtioned the ability to try out setting that have worked for other users. But if it won't work, for whatever reason, is that a basis not to try a new faster CPU?)
Thanks for any suggestions.