Which Legacy Mini is it? A better question is does CuraLE 3.6.37 want to load firmware version 1.1.9.34?
Next check would be to examine the start gcode being generated. You can open the printer settings, type ctrl-A, ctrl-C in the start gcode area and then post it here after clicking the Preformatted text tool above (</>).
Another option is to create a new printer profile and verify that the start gcode is the same as the printer profile you are using.
We are trying to make sure that the start gcode and the firmware are compatible. Do you have some older gcode files that worked? If so, we can compare the start gcode to make sure the current version of CuraLE hasn’t messed things up.
Is anything in this topic relevant?