@hazlin By the way, Android happens to use the kernel, Linux, except an extra-proprietary version.

BusyBox/Linux is indeed better than Android, but it's pretty sucky, so you'll probably want to install GNU.

Every single mobile chipset is malicious, so maybe it's best to just get a number from https://jmp.chat/ and then you can place calls and send SMS's with only free software from your gnubooted thinkpad (requires internet connection, but if you don't go outside, you're all set).