i have a huge problem with my n900...two days ago, i was on the internet and while surfing, i thought of updating my apps...so i went to xterm and apt-get update, then apt-get upgrade...i didn;t what saw what the answer was, and i hitted "y"...after lot of thinking, the answer was "your want to install a kernel, which is older than the one you have. do you want to downgrade?"......so, yesterday, my n900 run out of battery and it closed itself, like always....here is the problem...when i put the charger, the screen lights with the nokia logo, then it switches off..and after 10 sec, it fires up again with the nokia logo and then switches off again....all the time....no charging light, no anything + there is the icon on the upper right corner, wich shows that it's connected via usb, when it's not.....when i connect it to usb, the same thing happens, only that i can hear the sound when u connect a usb to windows, but immediately you hear the disconnecting sound, and the phone disconnects......did i brick my n900??

Just charge with an external charger and reflash it !

i can't flash it...because it keeps disconnecting from the usb, the maemo flasher doesnt recognize the phone, and i always have "suitable usb device not found"...isn't there a way to access the internal memory and somehow fix it? i think that this "downgrade", ripped up every software universe inside, so it may be kernel problem...that't why i tryied to flash only kernel, with no success..

Doesn't sound like a bricked device, just yet. Check the Wiki for info on how to flash, and make sure you do have a full battery before reflash.

http://wiki.maemo.org/Updating_the_firmware

If you have questions after reading that, please give some OS specific information of the device you are using to reflash.

You already stated that you didn't take the time to read the feedback from your terminal when applying apt-get upgrade. Perhaps it's best to forget about apt-get upgrade alltogether and use either FapMan of HAM to do updates.

You have to charge the battery to be able to reflash

hehe i know about reflashing, cause i have done it already twice........but i don't know what to do...i also unscrew my n900 and checked if the usb port had been moved....but everything is fine.....i went the battery to a local battery repair store, and they half-charged, with their desktop charger.....the problem is not the charging itself, but the continious and endless reboot.....can a kernel downgrade affect the boot and the usb-charging connectivity so much, that it causes "crashes"?

Half charged is not good enough. It needs to be charged much more than that. Without a full or decently full battery you will not be able to flash.

omg...flashing is not the problem, i told you already...but is a method of resolving the kernel issues.... the problem is tha i can't charge my phone, cause it reboots...

I've recently faced similar problem, so here is some advice for you:

1. Use a linux machine (eg. Ubuntu) to do the reflash. You can download the iso, boot it from a usb (guide here). You don't need to install it, just choose "try Ubuntu".

2. It's still possible to charge your battery without external charger. See this thread (read the documentation). Charge full and try booting. Again Ubuntu is recommended (if not a must).

3. If you can't boot. Try reflash your kernel only. If that doesn't work, try reflash the whole fiasco image.

4. If everything fails and you want to rescue the data, you can try entering mass storage mode with the link above. If that doesn't work, this will.

kk thank you a lot m8...i 'll try your solutions and post the results!!!