At the end of August I did a bunch of printing, cleaned up my workspaced, and turned the power off. Today I went to print using the same stored file (in octopart) and it's as if the printer has "forgotten" the offset from X0. I assumed (ha) that this is all stored in the filesystem. Could there be something stored in ram/flash that is kept while the power is supplied but the machine is off, then lost if the machine is unplugged for a few days?
I needed to relevel the bed (office temp dropped to 22), after that it came to its senses and remembered its offset. how odd.
