@reinob: U-Boot musb driver is totally broken. It some older version of u-boot it was possible to establish tty serial console, but after some time of usage it did something with n900 HW and after booting linux kernel it crashed. Full reset (removing battery) was needed. But I remember that I was able to use u-boot console via usb from PC. And I think that u-boot can use serial console also for loading kernels... But new musb driver which is in last u-boot now totally not working. And forgot for usb host mode. Only in linux kernel it is semi-possible (with helper userspace applicaion). Only thing which could be possible is to fix new musb driver for serial console tty support.