Yeah, had to do that so that I could use AGS 1.5 too. I will try another usb without AGS on just incase the settings for that are doing anything weird. (Not sure that should make any difference, but I don't know enough about how it works to confirm)
Having the exact problem with my A500 Mini as well. Download had the lha and an instructions file, I followed the instructions but maybe I'm missing something 馃