Ah, stupid me, did not read the doc properly. If you go to the page I linked earlier, it is pretty clear. Here’s how it really goes:
- Start Luban, connect to printer
- Switch to the “Workspace” section of Luban
- In the Console section where there’s “Send command”, type M1029 E2 (case matters, captial M, capital E) and hit enter
- Send M500 command to save setting
- Power-cycle the machine
→ Now the setting should stick and the port re-mapping is effective. It will stay until you repeat the procedure with M1029 E1 (getting back to default. Most likely this is not necessary, since the new controller will be on default settings anyhow.
Sorry for the confusion - and still: untested, may again not work 