Oh, my God!
Have you tried using another battery?

Neither a friend of mine nor a local store near by have a n900

The Nokia 5800 phone uses the same battery. It might be easier to find than the N900.

http://talk.maemo.org/showthread.php?t=37420

There you go

I had the weirdest thing happen me just now: My N900 was completely emptied because I forgot it in my jacket pocket when I got home. So I connected it to a wall charger, got the pulsating yellow light, everything was fine... Fine, I thought, let's let it charge for 10 mins and then I'll turn it on, when the juice has built up a bit.

After 10 mins, I pressed the power button, expecting to see the clear white led lit up when the phone starts. Nothing. Instead the yellow light stopped pulsating and began to glow steadily.

I pulled the battery, put it back. I tried removing the charger, connecting the charger again and still nothing. I even fooled around with holding the power button for a long time. But I could get no life on the screen what so ever and I could only get the glowing yellow light, but not the pulsating one, indicating charging.

Luckily, I have another full battery, so I pulled out the charger and the failed battery, put in the full battery and the N900 started just fine. I shut it down, put in the previously failed battery and it too started up fine. Without a charger connected at any time. When it booted, it showed approx 1/3 charge (that it got during the 10-15 mins i charged it before trying to switch it on).

I have no idea how this would've gone down if I hadn't found my secondary battery. I might very well be sending the N900 back for repairs now, because there literally seemed to be now way to turn it on. It almost seemed like it didn't understand the "electronics of the battery" until I reset it by trying another one.

I just had the same thing happen to me. What a serious pita. But I have pretty much recovered. Thank you Jayshire & ZackMorris for your posts. It gave me an idea that seems to have worked.

Jayshire basically put the thought that the battery charge was the issue. I had drained the battery during normal use (and it seemed to drain faster then normal), so I went to reboot it (won't do that again) and was going to let it charge afterwords. But he mentioned that by switching batteries his machine came back to life.

ZackMorris mentioned that he could get it to boot up by using RD Mode enabled.

What I did was:
1. Reflashed the USA rom, (I couldn't flash the emc rom)
2. Switched to R&D Mode
3. Booted it up (YEAH!!!)
4. Let it sit charging connected to my computer.
5. A couple hours later - disabled R&D mode.
6. Now it is booting up again properly.

I lost all my customizations, because of step #1. ;-( Step #1 may not be needed, but it was performed while I was trying to recover, before I figured out a possible solution by reading the posts. So for completeness sake I'll list it. But I suspect it may not be needed.

It appears there is something in the boot up sequences (normal & battery charge) that checks the battery; and then somehow fails and it then reboots. RD mode bypasses that, allowing it to fully boot. Once it is booted, charging works! Charging appears to also be a "software" process of some sort, because I noticed when it was off and tried plugging it in it would go into the same reboot loop. So getting it booted up into the os in R&D mode is the key to allowing the battery to charge, which then once the battery is at a sufficient level, you can reboot and disable r&d mode.

Oh and emc flashing seems to require that the battery be fully charged; I still haven't be able to do it -- but my battery isn't fully charged yet. Is there some hotkey like the 'u' that puts the device into flash mode?

Nathan

I'm pretty sure you don't need to flash it to get around the boot issue. Unfortunately mine had to be returned because it absolutely wouldn't boot up unless in R&D mode.

Also for those having charging issues, please invest in an external charger, they're inexpensive and can save you when the charge issue comes up.

I think these issues are going to be resolved in the next fw update, I think it's noted over at bugzilla.

Mine was like that until I let it charge for a while while booted in R&D mode. Once it charged for a while (several hours). I was able to finally reboot switch it out of R&D mode and it let me boot up normally.

Nathan

I wish leaving it on the charge would help, as i left it on charge overnight, and also charged externally for several hours as well, all to no avail. I have to wait till about the 18th to get my replacement :-(

No, it only "charged" when it was in booted up and in R&D mode. I also left it turned off and "charging" overnight and it didn't charge a bit.

Once I booted up I left it turned on in R&D mode plugged into my computer and then it charged (maybe it only works when it is charging via usb, rather than the the dedicated charger?)

Several hours later I unplugged it and it was about 75% of the way done. I was able to switch it out of R&D mode and it was working again properly.

Nathan