R2 usable without a screen?

You can use OctoPrint via the web interface. The offset can be done via GCode. Youc an print small test patterns (attached is a 1-layer example) -- size it to fit the bed in the slicer and then slice and upload to OctoPrint. Once there you can initiate the print and experiment with offsets.

You can also replace the screen yourself if you are so motivated. We have links to the various parts that work here on the forum -- the LCD is not very expensive.

http://community.robo3d.com/index.php?threads/replacing-r2-touchscreen.19684/

 

If OctoPrint is not available/working then the Raspberry Pi is indeed sick. Either the hardware or the OS on the SD card

 

The replacement screen is available through partsbuilt.com

 

What version of RoboOS software do you currently have? Current known good versions of software and firmware are listed in the R2 FAQ along with instructions.

Based on how you wrote your posting, I assume that the screen display works, but the touch portion does not. The touch function works through the GPIO bus of the Raspberry Pi.

Items to check out:

Is the ribbon cable seated properly on the Raspberry Pi and the LCD screen?
Are the connectors firm on the ends of the ribbon cable?
Does the touch function start working if you flex the ribbon cable?

 

Yes, I think the update of the RoboOS (Raspberry Pi) image is probably what broke your setup. Like @tkoco suggested -- check the FAQ for the correct versions you need to have installed.