If it can be done on the ADV it can be done on the 1290SDR as the hardware is pretty much the same.
Don't know why KTM hasn't released a pay for update yet as they did on the ADV.
Anyway as Jmann pretty much stated I wouldn't go there unless it is approved by KTM.
Several other ecu's software on the bike need likely updating too as it relies on the G sensors and countless other things to do it's job.
Only a dealer can do it anyway as a diagnostic tool is needed to load the software, and I'm petty sure they decline unless green light by KTM!