now i have charged it 8 hous, the power switch was down,not green.I tried to restart the Kindle by pressing and holding the power switch for 20 seconds,but it is not useful.I recharged my kindle ,the power switch still is yellow,about 1 hour is down ,not green.
I downgrade my kindle refering to the wiki:
https://www.mobileread.com/forums/sho...d.php?t=186076