I spent a long time searching before posting.

My N800 goes (very rapidly) to a screen with the NOKIA logo and a little wrench icon as shown below when powered on.



Holding down the Home key while pressing the power button does not give the USB icon so I can't find a way to reflash the device or do anything using the flasher tool (flasher just always says 'Suitable USB device not found, waiting')

The above screen appears for about 30 seconds when the power button is pressed, then the screen goes black. Pressing the power button again gives the same result. No change whether Home key is held down or not.

I removed the Mini SD card to no effect. And of course I've tried to pull the battery.

Your tablet is in R&D mode. Search on Wiki at Maemo.org

I did search there and I found nothing helpful to this situaion. The only way it shows of changing the R&D mode setting is using flasher and I can't use flasher if it won't go into USB mode. Nothing tells me how to get it so I can use flasher again when this boot screen is all I get , no matter what, even when the Home key is pressed. I can't use the flasher or a root shell if all it will do is show this screen.

BTW, this just happened out of the blue. The device was working fine and then one time I went to it, pressed power to wake it up, and this screen is all I got.

So what is the trick to get it to connect with flasher again?

Oh... missed the second part of your post
I have to admit that I don't know of any way for making it work. It might be a case of return to Nokia

I have the same problem - also if I plug in the charger, it cycles through booting and turning off!

Could this be the problem? - "Therefore all systems involving Li-ion batteries are equipped with a circuit that shuts down the system when the battery is discharged below the predefined threshold"

I have the same exact problem. I just tried to restart my tablet about an hour ago and I got the same thing.

I do get a little progress bar at the bottom and then I can hear the nokia chimes but the nokia logo and wrench never go away.

I tried booting it into USB mode and it won't boot to USB mode either.

The only thing I did was update some components last night. I had to restart it today because of some bluetooth issues.

So am I screwed now..

I've gotten some of these out of R&D mode following instructions I found on the web, and I'm pretty sure it was on the maemo wiki site. I had to use the linux flasher though, it can't be fixed with the Windows application.

If I can find the link I'll post it.

Well at least I know where to look now Thank god for ubuntu.. I am fairly comfortable using linux so if you find something please post it!

Thanks