[PROBLEM] How to install with serial console?

[ceving]

I connected a B+ with a serial cable to my PC. Before I have changed in the config.txt the console from

Code:

console=tty1

to

Code:

console=ttymxc0,115200

as explained here. But the only thing I see during boot is

Terminal

Uncompressing Linux... done, booting the kernel.

The initrd does not honor the boot parameter. How can I fix this?