Marlin 2.0 Bug? Bed centering issues on Lulzbot-Prusa Mini Hybrid

Hi all, new to this forum. I’m currently in the process of upgrading my Lulzbot Mini into having a Prusa Mini bed. Making good progress on it. Decided that with removing the bed leveling washers i needed to flash custom marlin firmware. I grabbed Marlin 2.0 and got nearly everything configured and even got a test print (although it needs some tuning). The problems arose when i tried to follow this guide to center the print on the new print bed. https://www.youtube.com/watch?v=Dqt8cUtzOfs

When i went to uncomment the //#define MANUAL_X_HOME_POS & the //#define MANUAL_Y_HOME_POS i ran into really weird problems. I was able to get the x-axis to center although instead of being a negative value it was positive. But when i went to put in the values for Y i got some weird grinding sounds as if the stepper motor was running the wrong way. I tried switching the y value to the opposite since the y axis is flipped, but either way it does not work. Additionally when inputting a G00 X90 command sometimes the Y-Axis will move too! This should not be happening! And only seems to cause issues when the #define MANUAL_Y_HOME_POS is uncommented. I’m wondering if i encountered a weird bug in Marlin 2.0. Some have suggested that Marlin 1.1.9.1 is more stable.

Anyway, any suggestions? Comments on my project? This is the first time i have dug into marlin on my own.

-Andrew

So I’m fairly confident this is a bug and not just on Marlin 2.0.

The new information i have is this:

Just flashed the firmware and did a test to see if Y-axis homes correctly and it does. Then did a G0 Y10 command to see if it moves in the correct direction and it does. Tried a G0 Y90 to confirm and it does.

Then uncommented manual home positions to 0 for testing.

#define MANUAL_X_HOME_POS 0
#define MANUAL_Y_HOME_POS 0
#define MANUAL_Z_HOME_POS 0

Did the same procedure as above: flashed the firmware and did a test to see if Y-axis homes correctly and it does. Then did a G0 Y10 command to see if it moves in the correct direction and it does NOT! It goes the wrong way!

Then to confirm this i changed

#define INVERT_Y_DIR true to #define INVERT_Y_DIR false and reflashed.

I then expected my Y-axis to go the correct direction, but fail when homing. It went the correct direction when i did a G0 Y10 command and a G0 Y90 to confirm. Then i did a Y-Home and it went the wrong way and crashed.

I have tried Marlin 1.1.9.1 and have reproduced the bug.

It does not do it on the older originally lulzbot mini marlin source, but it still has bed levelling enabled as i can’t disable it without breaking the steppers.cpp file.