Hello. I got a notification on status area that Kernel power user update is available clicked it, application manager launched and i actually clicked Update all, and it started downloading and updating.
It also installed i2c-tools, and updated kernel power user. I made backup before , installed all , and restarted then i only see Nokia and then it dims, doesnt start at all. What can i do? I also have some files in internal memory that i need.. Please help. Thanks in advance

You need to flash the kernel only
flasher-3.5 -f --flash-only=kernel -R -F RX-51_2009SE_20.2010.36-2_PR_COMBINED_MR0_ARM.bin

Pluged USB cable or wallcharger?
If yes then unplug them. Maybe it's caused by the Reboot bug of KP.

@willi6868 yes it was plugged usb, unplugged it but still didnt worked, so i removed battery and left it 2 mins like that, then put it back and it booted. All good now, hope it works with battery patch. Thanks all for answers.

Hi i have a similar issue n900 wont boot, turn device on it brings up the nokia screen it dimms down then shuts down, when charger or usb cable is hooked up it will bring the nokia screen up then shut off until the cable is removed, it all started with a camera issue after i installed power kernel so i downloaded rootsh and folled the uninstall procedure from the forum then when i did the phone restart as instructed i got stuck with a non working n900 please help thanks all