[beagleboard] Serial console lost after kernel upgrade (beaglebone)


I'm using a BeagleBone rev.A6 and successfully compiled custom kernel
following Robert's tools and sources.
The board boots up successfully and the changes on the mux are the ones
changed on source code. I haven't changes the original u-boot inage that
came with Angstrom distribution

The problem is; I have lost the serial console output (even u-boot does not
output anything), I have tried passing explicit parameters like
console=ttyO0,115200n8 without success.

So "even u-boot does not output anything", i'd really first start
looking at u-boot before blaming the kernel...

At least there is an issue with u-boot, as it do not display anything, but I
haven't changed anything in /boot partition.

Any ideas?