fei-d
1) Don't worry, you'll unbrick it.
2)
https://www.mobileread.com/forums/sho...&postcount=799
Would be nice to determine what was the cause for the brick though to avoid it in the future. Did you have US 1.1.00.18040 firmware when flashing? Did you have many books/files on internal memory?
Did installer log report any errors?