Great news, worked for me, , last whole week i was frustrated and reading many threads and information on this issue. In my case i can say its not at all a hardware problem. It was problem of my laptop with Windows 7 which was not flashing my n900 properly.

Starting form the beginning, one day my phone suddenly started a loop of rebooting. then i tried to reflash the device (not eMMC Image) (i.e. flasher-3.5.exe -F RX-51_2009SE_20.2010.36-2_PR_COMBINED_MR0_ARM.bin -f). My phone atleast stopped rebooting but i end up with another problem of No Connection to service provider.
I tried to reflash 2-3 times more but same problem, then i realized that i was flashing with windows 7 and the process of reflash was not completing properly (it used to complete in 2-3 seconds don't know how) and since i was not using "-R" in the script my N900 was not restarting on its own. and if I restart it was showing an error "All telephony....". finally I tried from my Office laptop which has windows xp and in the first attampt it showed me "flashed successfully" (not sure about the message after completion of reflash, coz i did not bother about the message that time). and when i booted n900 it started without any error. one more important thing, while flashing i forgot to insert my sim card. so when i tried restarting with sim card, there was no error. I hope my experience would surely help some one. I love my N900 .