Some E3's can be difficult to flash, use a 2gb micro sd card formatted to FAT32 and extract the firmware onto the root of the micro sd card, move jumper over as-per bitmain instructions.
Honestly?
there is a file located located in root called "core" which I am told is just a core dump file and taking up a ton of space which is preventing the firmware update from installing, I just ssh to the miner, locate the file in "/" and remove it with "rm core" then exit and run the firmware upgrade from the web gui without issue, it was really easy.