Hello,
I was trying Archlinux as indicated: https://www.olimex.com/Products/OLinuXino/iMX233/_resources/ARCH-README.TXT .
bug fixed, now login by debug cable possible.
In file '/etc/inittab'
s0 was directed to /dev/ttyAM0 , to be fixed as /dev/ttyAMA0.
Regards
PO.