Ohh such a good question! haha I was wondering whether I could download Arch ISO with the normal Android I theoretically brought with me and flesh a MicroSD using the smartphone itself.

Well, regarding to download I could use Transmission or any torrent client for Android. For checking the sha256 hash I just did a quick test here and it's possible with Termux:
 https://image.nostr.build/0336c498e4c5babb0627ac82e555d6cb517ee22def6c8afee1b84ad32c573984.jpg 

The only open question now is whether I can flesh a MicroSD using Android, I will take a look at this specific topic and bring the answer later haha 

 Arch ISO and Nixpackage with the complete setup in an Onionshare and Etchdroid.

The whole plan is setup haha thank you Sjors Provoost to support my paranoid mental experiment haha

https://f-droid.org/packages/eu.depau.etchdroid/