This app was mentioned in 2 comments, with an average of 1.00 upvote
The Android Ledger app to setup the Unplugged has been published!
https://play.google.com/store/apps/details?id=co.ledger.wallet
(please uninstall the other Ledger Wallet app before if you have it already, this app replaces the old one).
Ah, so the app that replaces the secure card offers 2FA by phone. If the PC you use is compromised and your keystrokes are recorded, you gradually reveal the entire keymap to anyone who's watching. Switching to 2FA by phone eliminates that risk. In order to execute a fraudulent transaction with this setup, someone would need to hack your Nano (which won't even boot up if the firmware has been changed), your PC and the 2FA app on your phone. You mentioned you don't trust the app, though.
https://play.google.com/store/apps/details?id=co.ledger.wallet&hl=en
Second is the main subject of our chat, Ledger Trustlet. This is the app that gets installed in the Trustonic Trusted Execution Environment to emulate a Nano. The Trustonic TEE is primarily found on newer Samsung devices (S6 and Note 4 and newer) but can also be found on specific models from other manufacturers. You interact with the Trustlet through mobile apps like Mycelium and Greenbits the same way you would if you plugged your Nano directly into any Android's USB port.
https://play.google.com/store/apps/details?id=com.ledger.wallet.bootstrap&hl=en
Here is more information about the Trustonic TEE.
https://www.trustonic.com/technology/trusted-execution-environment