Taz 5 screen blank following firmware upgrade

I am a newbie using an old Lulzbot Mini 2/SE/0.5Fitted with a Taz 5 control. Every time I pressed Start Print to make a 3D print a notification came up that there was a firmware upgrade to upload. I have ignored this for several months until I became comfortable that I could perform the upgrade. I recorded the values for the esteps that I would need to reload after the upgrade. My laptop was connected through a USB cable and the TAZ panel was illuminated . I started the upgrade.
After a delay the printer table ran to the far extent on the Y direction and chattered against the end stop and the extruder nozzle was bubbling hot filament from the extruder. I switched off the powere to prevent damage.
When I switched on again to rest the printer the control panel was illuminated but totally blank.
My laptop is not communicating withe the printer although it say that it is connected.
Pushing the control knob on the Taz 5 has no effect…
Has anyone any ideas that I can try to restore control of the printer.

What do you mean by “Lulzbot Mini 2/SE/0.5Fitted with a Taz 5 control”?

I believe the previous owner fitted the Taz 5 control as an upgrade.
When I go into Settings - Printer it comes up
lulzbotMini"SE/ 05mm
That is all I can tell you.

So it’s an original Mini, (not a Mini 2), that has a RepRap Full Graphic Smart Controller (the same one used on a Taz 5) connected? If it has screws for the Z axis, rather than belts, this sounds right.

Make sure you’ve got the correct printer added in Cura LE (making sure Graphical LCD is selected):

When updating firmware, manually point it at Marlin_MiniLCD_SingleExtruderAeroV2_2.0.0.144_aded3b617 in the “C:\Program Files (x86)\cura-lulzbot 3.6\resources\firmware” folder. If you were back on 1.x firmware, it won’t automatically update to 2.x firmware.

If the previous owner may have done a custom firmware for some hardware modificationsyou’d need to get a hold of the old firmware and re-flash it.