My first Kindle would freeze after sometime in sleep mode, and would need a hard reset. Now my replacement has this random reboot problem. This just SUCKS!!! Especially as I love the device itself.
As with this other thread (
https://www.mobileread.com/forums/showthread.php?t=97499) the problem seems to occur when I'm travelling - ie, after reading on the tube, when i get home - its rebooted. But when its sat at home overnight - no problem.
So... i guess i need to go through the replacement process again........