I have a Nokia N9 64GB that I've used without problems for years. Some time ago, I started noticing that the N9 was getting slower and losing battery life. This progressed until the N9 would make a "whimper" "dead battery sound" and turn off. I tried charging it but the N9 would just vibrate briefly, the charging LED would flash and then turn off. Then, it would turn itself on again, in an infinite loop. Eventually the phone would not even turn on and no vibration was exhibited and no LEDs turned on. Anyways, when I got the time to investigate the problem, I partially disassembled my N9 until I could access the battery. And, what do you know : The battery was *bloated* . I checked it with a multimeter and it read 0 volts. So, I got a new battery for the N9 recently. After installing the new battery, the phone didn't seem to want to charge. After a while though, and after unplugging and re-plugging the N9's USB connector into my laptop, the LED lit up. It would light up dimly white, vibrate briefly, and then the LED would light up brightly for about 30 seconds or so and then blink 3 or 4 times and then turn off. After having my N9 plugged into a Plugable fast charging USB hub with a generic micro-USB to USB type A connector, and, after having turned the phone back on and off again it finally "came to life", or so I thought. The Nokia logo and a small USB icon were displayed but then, almost immediately, a screen with a caution symbol would be displayed which read "Warning! you have modified the device software" . My N9 would display this screen for a while and then turn off. I did modify the software in that I disabled Aegis and rooted my N9, but, it never threw this warning screen at me before.

I have never flashed my N9's firmware in such a way as to brick it and before it died, it was working normally. Now I'm stuck on this warning screen. I've tried multiple methods of trying to un-brick the N9 but when connected via USB to a Windows or Linux box, the N9's USB connection doesn't even show up ( eg. "sudo lsusb -v | grep -i -P '(Nokia)|(n9)'" shows nothing).

I'm also considering that I was possibly using only charging USB cables and I'll test the N9 again today with a data/charge cable. My hypothesis is that the warning screen is blocking the charging code from operating and that the battery goes below 10% after a little while. But, I don't know how to get the N9 to bypass the warning screen.

I have all the service manuals and schematics, and I'm hoping that might help. The reason is that if my phone is truly dead, then I can suck off the user data from the eMMC using a ribbon cable and an SD card connector. I could then swap out the system board and then re-flash the phone with my original firmware and user data and it should be back to normal. But, I *really* don't want to have to do this because it's such a PITA.

Any suggestions or help would be greatly appreciated.

Thanks,

jdb2

EDIT : I said "but I think I'd have to use JTAG for the NAND flash root/boot file system", which is of course wrong for the N9 -- I was thinking of the N900. Sorry for the brain fault :P