i had the same problem with downgrading. the golden update from entourage edge website does not have enough mb so that could be the issue it should be 216 and the website was like 133. the one found at dusty works. here is the link to the forum that has it
https://www.mobileread.com/forums/sho...134237&page=11 it at the top just click on the the link that is in the post
second solution would be to look under the file explorer to see if it is update.zip.zip which is reason why my downgrade never went through and I tried 8 times with different ubs and sd cards and different files. once i removed the extra zip the downgrade with smoothly
use for explore your storage device and see what the file name is and rename if it is not update.zip and check how many mb the file is.