To update the BIOS without Windows, install UNetBootIn and use it to put FreeDOS on a flash drive. Now extract the e.g. v.3305.zip to it and reboot the machine. Press F12 in the right moment and select your USB flash drive from the list. Press ENTER when you see the boot: prompt, then launch the Default configuration and select to boot FreeDOS without any drivers.

Now you should be at the A:\> prompt which is the emulated floppy drive. Change to C: and execute 3305.BAT.

Gateway BIOS

macles points out that there are netbooks with the same hardware as the AAO and therefore the BIOS file is compatible. You can download the Gateway-BIOS from there. In the comments you will find tips and tricks if your sound or function keys are not working after the update.