When installing Mycelium, the first time it asks whether to start a new wallet or restore a previous backup.
However, once a new wallet is running, is it still possible to import a HD backup (12 words) from another wallet? Or better yet, (temporarily) switch to a different HD wallet, by entering 12 words?
The problem is: I recently installed Mycelium on my phone, started a new HD wallet, but now I suddenly doubt if my old wallet still had some bitcoins left. I still have the 12 words (for both the old wallet, and the new one). But I can't seem to open or restore or import an old wallet anymore, once a new HD wallet has been created??
I don't know Mycelium well enough to answer, but you could make a new account on your Android device (in settings -> users), switch to the new user, and run Mycelium as that user. It will be like running Mycelium for the first time so you can import your old seed.
It's kind of a sledgehammer solution but it should work.