Did you factory reset the TouchPad as well, which is the post after the one linked above? If that doesn’t work, then you’ll need to contact Support. In the mean time, you can do a USB controlled calibration/leveling, but you can’t do it with a heated bed (not needed):
11 x 11 Automatic Bed Leveling (Calibration)
You will need to connect your computer to your Snapmaker using either Luban (USB only) or Pronterface (USB only) in order to do this. Then navigate through the menus on the Touchpad, and tap the Control button. If your Snapmaker prompts you to home, do that now. Then execute this first macro:
Auto-Level (11 points)
G28 ;Home
G1029 P11 ;Set auto-level mesh to 11x11
G1029 A ;Start auto-leveling
Once the Snapmaker stops taking measurements, use the Z offset buttons on the TouchPad to adjust the Z-offset (do not use Luban or Pronterface to do this). Use the calibration card that came with your Snapmaker. If you have lost the card, or it is damaged, use a 0.1mm feeler gauge.
Lower the 3D Printer module using the Z Offset buttons on the Touchpad until you feel resistance, and then back off until you no longer feel resistance. Use the smallest amount of movement allowed when doing this. This DOES NOT need to be perfect, as you can adjust the Z-offset while printing your first layer. The Z-offset changes made while printing are saved automatically in the TouchPad, and survive a power cycle.
Once you are done with the Z-offset, execute this second macro:
Auto-Level Finish (set Z-offset first)
G1029 S ;Save settings
G1029 D0 ;Confirm auto-leveling is on.
M420 V ;Verify auto-level results
G28 ;Home
If you don’t want to perform an 11x11, you can anything up to it. I recommend only using an odd number, as even numbers will not probe the middle of the bed.