For PS3 Firmware (OFW) 3.41 and 3.55 only.
Install qa_flag.pkg and run it.
If it beeps, it worked; If not dump the debug messages via udp_printf (on Linux) and send that to the folks at gitbrew.org.
Reboot your ps3
Go to [Network Settings] under [Settings] (leave your cursor highlighted on it) and press or hold L1+L2+L3+R1+R2+DPad Down
source code (git repo): git://git.gitbrew.org/ps3/otheros-utils/qa_flag.git
źródło:ps3.dashhacks.com