Try Porkupan's restore package. I had better luck with that when my reader was bricked.
http://projects.mobileread.com/reade...estore-set.zip
You'll probably want to flash update your reader afterwards since it is based on an older firmware.
And not to be redundant, but here is the method:
https://wiki.mobileread.com/wiki/PRS...C_sd_rescue.29