G28 crashes Z after failed M48 with separate endstop and probe inputs

I have a BLTouch and a Z endstop on separate inputs and they are configured as such.

`Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN` is disabled.
`USE_PROBE_FOR_Z_HOMING` is disabled.
`Z_SAFE_HOMING` is enabled.

Probe offset is set... the wizard was better at this than I was.

If the printer is un-homed and M48 is sent, I get the error, `Home XYZ first`, as expected.
So, I issue G28. X and Y home then move the bed center as expected.
Z starts homing, but never stops.... even past the endstop. I have to E-Stop or power off the printer to stop the Z movement.

If I reset the printer and never send an M48, G28 homes all just fine from whatever source it is sent from.

I will add that if I issue G28 first and all homes, then I can issue M48 and the repeatability test performs flawlessly and, this morning, I get a standard deviation of 0.00124.


This printer is an Anycubic Korbra Max that I have changed the mainboard to an SKR 3 EZ and changed the screen to a BTT TFT35 E3 V3.

Using Marlin bugfix 2.1.x dated 2023-12-12

Edited 1 time(s). Last edit at 12/27/2023 04:11AM by Taannoo.

I have since updated Marlin to the bugfix-2.1.x 12-31-23 nightly build. I need to test again this way. I believe I got misled.

When M48 gave the "Home XYZ first", I left it there. I did not try to home.

I was re-reading this post.... I need to try this again.. in this order.