Hi everyone!
I finally made it installing Arch Linux ARM on both Fox Board G20 and AriaG25 from Acmesystems srl.
Both devices are ARMv5te Atmel AT91SAM9G2x MCUs clocked at 400MHz with 64MB of RAM (Fox Board G20) and 128 or 256MB (AriaG25).
Fox Board G20: http://www.acmesystems.it/FOXG20
AriaG25: http://www.acmesystems.it/aria
Both the devices are running with the ArchLinuxARM-armv5te-latest.tar.gz rootfs with linux-3.12.
However the Fox Board G20 reboots every time I'm halting the system (maybe the watchdog doesn't stop, I don't know...).
Nothing wrong so far with AriaG25.