Since quite some time now a new blog-article – mainly to conserve this knowledge:

I modernized the AIS-Setup in my boat and am now selling my trustworthy Simrad AI50 AIS transponder. But how to reset the MMSI so that a new user could use it?

That’s what I partially found out on the net and partially figured out:

• Format an SD-Card (capacity smaller or equal to 2 GB) with FAT32.
• Create a text-file in the root directory with the file name
  MMSIReset.txt
• Put the string Y91%p7kQ@21#aV in the text file and save it.
• Open the back of the transponder, put the SD card in.
• Switch the transponder on.
• Enable logging in the menu.
• Follow the instructions to reset the transponder