Answered Homing Z show -001.0 on LCD

Chasing my tail once again, after making another attempt at manually leveling the bed (x axis, leadscrew and paper method) and doing a Z "home", it ends up displaying -001.0 on the LCD display.

If I raise Z, by 1mm, in this case via Octoprint, the LCD shows +000.0. I can get nothing between the bed an nozzle. If I raise it another 1mm, the LCD shows +001.0 and I can get a bit of paper between the nozzle and the bed.

How should this affect printing, specifically how to set "Z-offset" and/or, how to save in firmware the proper place for it to save a new value for "z-zero"?

 

Well it is an R1 "plus"-ish. Meaning Ive done the lead screw mods and "stuff". It has no "bottom cover", so it is a pretty early version.

The firmware Marlin, but exactly what version is not certain. I've complied it in Arduino but there is no version number I've been able to find. The LCD on startup flashes by too quickly for me to read.

The title of the file was ROBO3DR1PLUSV2 and this snippet is from the file:
/*
This firmware is a mashup between Sprinter and grbl.
(https://github.com/kliment/Sprinter)
(https://github.com/simen/grbl/tree)

It has preliminary support for Matthew Roberts advance algorithm
http://reprap.org/pipermail/reprap-dev/2011-May/003323.html
*/

/* All the implementation is done in *.cpp files to get better compatibility with avr-gcc without the Arduino IDE */
/* Use this file to help the Arduino IDE find which Arduino libraries are needed and to keep documentation on GCode */

 

Yes. I pondered where to put it and opted for Prusa. Only thing in Ocotprint, is what what I put in for a "cancelled" job.