Problem with Kindle Paperwhite 3 Jailbreak. Please help!!!!!

Hi everybody i jailbreaked my kindle yesterday, just because i wanted to install KOreader. But after trying it out i decided to reset the device because i liked it as it were before jailbreaking. Afterwords i read that a reset does not remove the jailbreak, and i realized that my device won't update to any firmware at all (i download the firmware from amazon.com and transfer it to the kindle as usual) but the update button on the device remains grayish, as there weren't any update file/firmware transferred to it :/. Im now stuck with firmware 5.7.2 which is the bin. file i installed from the 'how to jailbreak' guide. I also installed the Hot fix file after i jailbreaked it. And i have tried the whole day to find out how to remove the jailbreak or at least be able to update it to the latest firmware 5.8.2.
My kindle is a Paperwhite 3 wifi from europe.
I would really appreciate if anyone could help me with this problem.