Request: Make Changes To Preferred_network_mode Permanent

[MarkyO]

Changing the preferred network type in engineering mode always reverts back to default on reboot. This is annoying as many connectivity issues (slow data connection, disconnected phone calls) are fixed when "LTE/GSM auto (PRL)" is selected.
Is it possible to make these settings permanent?
I work around this issue with a patched boot.img with init.d support and a script. Would be nicer, if the chosen setting would stay.