if you power the unit up whilst the console is running … do you get any messages?
also on your Mac, If you look at “System Report”, does it show it connected to the USB port, and what is the device labelled as?
Im assuming (as you think its dead) you are not getting anything on the screen as it boots up?
(e.g. not even the firmware version)
are you able to redo the hardware recovery still?
It might be an idea to do a video showing what happens when you do this, and include a copy of the log it produces.
does loading the older firmware work?
what hardware version of the E1 ?
a couple of notes, to perhaps allay your fears a bit, that things are perhaps not as ‘serious’ as they may look 
it probably is powering on… just you cannot see anything, if the firmware is not running “correctly”, you’d probably not see very much, and even the display backlight might not come on…
so it would look pretty dead…
these things have a protected bootloader, which handle things like the firmware updates.
so, firmware updates cannot really brick the device.
instead most likely the firmware is crashing… so it just appears dead.
internally, in the E1, the ‘firmware’ thats being updated is loaded on to a micro SD card.
whilst very unlikely, potentially this can get corrupted… this can make things go awry.
its a little fiddly to get access to it, but its very possible (with care!)
so worst case , it can be changed and have a new firmware image placed on it.
my point really is… whilst it may look like its a hardware failure, dont worry too much.
most likely the hardware is perfectly ok, and you’ll be able to get it up n’ running
edit: ah, just noticed Martin has replied on a different topic … so hopefully you are already up n’ running again.