ya i flashed to PR 1.1.1 version 3.2010.02-8 global release as im living in ireland, no updates i can see on the app. manager.

any other ideas, i cant think of anything else which could be causing this!

Hello, I am having the same issue here.
I had my rootfs full, so I started deleting apps.
Later, I rebooted the N900, and the simcard was suddenly not recognized.
Tried other simcards from other operators, but for no effect.
Rebooted again, flashed the latest firmware (tried US and Global), but nothing seems to help.
The device takes a longer time to boot than before, probably trying to connect to the operator.
All other functions work properly.

I'd suggest backing everything up and reflashing both the firmware and eMMC. If that doesn't help, take it back & get it repaired/replaced.

I'm having exactly the same issue on mine! Already tried flashing to different fw without any results. Today in the morning it worked for like 5 minutes just after a reflashing.. but since then.. nothing!

My phone feels like a paper weight!
Any other ideas anyone?!

Borrow another SIM card to check it's not just the card that's faulty. Otherwise it's a repair job.

I have similar problem but mobile doesn't start when i insert sim card. it just hung up with five dots. I reflashed with fiasco and eMMC images. Don't know if global image will work.

ok after flashing also didnt work, i brought my phone to a Nokia Care point,
this will send the N900 to Nokia itself, so i dont have my N900 at the moment
What to do now if PR1.2 suddenly is released???

I've noticed this problem has occurred quite a bit, as it happened to mine as well. However i just fixed it and if anyone has got this problem please try this as it solved my problem.

-Turn your phone on until the message comes up.

-Tap the screen until it goes away and then set it to offline mode. (Tap the notification area/system tray next to the clock and it should be on the right)

-Plug your USB charger (USB end) into a USB that is on, like a pc usb or game console usb.

-Then plug the charger into your phone.

-When the mass storage and pc suite selection screen comes up, don't click either and turn off the phone.

-Once turned off, make sure it is still charging by checking the orange LED pulsating.

-If it's not then do this all again and make sure it is.

-Now turn the phone on, and exit offline mode when prompted to. If you are not prompted by the time you reach the desktop, turn the phone off and repeat until you are. (after the 3rd attempt try enabling it normally via the notification/system tray)

-If it says you've got a 3G signal then you should be connected to your network. Before doing anything, text message yourself and await the reply, or ring your network to confirm it is working.

i hope this helps.

Tips:

Make sure your phone has the latest update package. You can get this via the nokia software updater on the website. However this doesn't always work. If not then connect to wi-fi on your phone and go to the app manager. Make sure the extras and other extra repository things in the application catalogs are deleted or disabled if you have added any. Then update by selecting update all rather than the manual selecting the update or you will be greeted by a "OTA update is unavailable" or something similar.

Also, call up your contract supplier and get a refund for the months you haven't been able to use your phone. So for me that will be 5 months of £40 payments. I was also offered a free extension of 5 months to cover this.

Ok, update on mine;
It's working 100% for one and a half month now. What I did? Nothing! I got pissed back then and just put the phone away (with battery detached) ina drawer and forgot about it. After a long time, I got it back bc I was going to send it over to a friend in Finland to get it fixed but before I needed to be sure that the problem was still there. Result: worked 100% since then.

My veredict? Humidity! My phone also had a issue with the keyboard slider sensor (that kept triggering off alone) and that one started when I travelled to oh'beautiful'rainy London. And of course I walked a lot in the rain. Also, the day it stopped recognizing the sim was at my graduation party (which also rained quite a bit).

As far as my electronics experience goes this humidity-related problems are "known" to go away after long periods of time, resting, in dry environment.. that's what I did and it worked. It seems a good theory for me..