I recently reset my phone to factory condition and forgot I had Mycelium with a small share of a bitcoin on it. Not too much, so it won't really harm me if it's lost, but enough to be annoying.

Went looking through my notes for a backup and found something in this form created in July 2014 with whatever version of Mycelium was current at the time:
xxx xxx xxx xxx xxx x
Every x is a seemingly random capital letter. After re-installing Mycelium, I can't find a way to enter this as a seed code, instead it asks for a word list of at least 12 English words.

Does anyone recognize what this backup code is and can tell me how to use it?