Maybe something got installed that messed up the boot up.
Maybe a device driver was added to the DEVS: folder and isn’t working right.
How do you fix this if it is something that happens before you can get into Workbench to change it?
Well, you could do old-style and boot from something other than the harddrive (like a floppy or CD). Or, for those of you that aren’t afraid of a command line interface, you can start up your Amiga, and have it skip the startup-sequence script and take you right to a promnpt, where you can copy, delete, rename, etc and back the changes out.
Well, I knew how to do this on Classic Amigas: hold down both mouse buttons as you startup. You’ll get into the early startup screen. From there, you can change a few things, check out the expansions attached and click the “Boot without startup-sequence button. The caveat was that it had to be a mouse plugged into the real mouse connector. Having a USB mouse on a USB connection wouldn’t work as the USB software stack wasn’t started until after the UI comes up and then it is too late.
This trick didn’t work on my AmigaOne XE and Micro-A1C boxes. It was only last week that I found out how:
Hold down the left CTRL button on the keyboard when it is doing the initial kickstart files loading and before it goes to the splash screen. Then, you get to the command line.
The caveat here, at least for these machines, is that it has to be a mouse plugged into the PS2 (round) mouse port, not a USB mouse, which I’m assuming is the same reason as with classic machines.
I hope that helped someone!
Mambo's Amiga Blog 