Unknown error in bootloader during unlock after crash With my ACER a700, Android crashed. Now, each time I turn it on it starts in fastboot mode. I tried to unlock bootloader to install Cyanogen, but after command line I have an response like "Error: Unknown error".

Is there a possibility to reset completely the device in order to reinstall a ROM?

EDIT:

I downloaded rom from this link and move update.zip onto SD card. I would boot in recovery mode but I can't, because of bootloader. I have the following output:

Booting failed
Bootloader vJB-663b3d3: Starting Fastboot USB download protocol


It seems I have not recovery menu. Also, I can't doing 'factory reset', I have the same failed.
The issue can be solved by flashing stock firmware to your device. 

Download the firmware and flashing tool from here.

Edited: List of A700 ROMs and updates from XDA Developers + Flashing procedure.


Another download links