Acer DA241HL - system reset from bootloader The Acer DA241HL is a 24" Smart Display which has Android installed but also had HDMI input so you can use it as a second screen for a laptop or similar too.

Anyway, I've been able to reboot into the bootloader using adb with the Acer DA241HL connected.

However, it doesn't show up on fastboot devices nor adb devices and only stays on the boot options screen for about 5 seconds before it seems to turn off completely.

At the top, it explains that pressing  or  allows you to move up/down in the list of options (bootload, restart, shutdown, reboot ? something like that), and then pressing the power button to select the option... however this is not a tablet or a phone, it's a "Smart Display" and the Volume Up/Down options don't do anything but turn the volume up and down for the screen (it's like it's not sending those buttons directly to Android, but only to the screens built-in speakers).

Pressing the power button when on the bootloader doesn't seem to do anything either, I've had to press the power button multiple times before the machine reboots back into Android otherwise it continuously boots into the bootloader and then shuts off after a 5 seconds.

Does anyone know how I can fully system reset (as in roll back all the firmware updates I performed) this device?

I've tried pressing and holding Volume Up with the Power button to boot into the bootloader 'manually' instead of using adb but it didn't seem to work...
Summing up from the comments:


No "reset" will ever roll back any system updates applied. For that, you would have to re-flash the original ROM.
For the device to show up with adb devices or fastboot devices, you must have your computer configured accordingly. If your computer runs Windows, you will need a special driver (Koush's Universal ADB driver might help you out here, in case you cannot find a specific driver for your devices). If it's Linux, you might wish to consult my answer here, for a Mac it might be similar. Further helpful hints can be found via our adb tag-wiki.
As you have multiple identic devices, some updated and some not, you should be able to utilize dd (see also this wikipedia article for a starter) to clone all partitions of one device and apply that to others. As partition structures are quite device specific, I cannot give you accurate details here; a little research might be helpful especially on sites like XDA Developers. A custom recovery can be used for this as well: check out our nandroid tag and its tag-wiki for details on that.