Preparing an SD card using an Android device

Yep! Network installation would be nice but won’t work in this scenario. You need to update the firmware which requires writing a microSD card. Also it requires screen and keyboard which I guess you could plug in.

A bootable thumb drive with the imager on it could be made to pull down the latest image and burn the image to the installed SD Card…
Or boot a full zynthian and have an option in the menu to image the internal SD card.