I am building a Raspberry Pi Phone. I have some questions about the OS and parts

[bigbangbilly]

I am building a Raspberry Pi Phone. I am aware it has been done before and there is an ongoing project making one now.

Is there a bootloader that allows booting to a usb?

Is there a way to boot Lineage os from a usb like from berryboot?

What GSM/LTE 4g module do you recomend? Can a USB module work with android?

How do I download drivers for an android?

[klricks]

I am building a Raspberry Pi Phone. I am aware it has been done before and there is an ongoing project making one now.

Is there a bootloader that allows booting to a usb?

Is there a way to boot Lineage os from a usb like from berryboot?

What GSM/LTE 4g module do you recomend? Can a USB module work with android?

How do I download drivers for an android?

A RPi can boot from USB drive or SD card.
Regarding Lineage OS..... Raspberry Pi is not on the list of supported devices so no can do: https://wiki.lineageos.org/devices/
All questions about installing Android on the RPi should be directed to the Android forums.
Start with the links here: viewtopic.php?f=73&t=71658