Hello
I have a 4g lte Chinese mifi router with msm8916 chipset.
I think that model is MF601STC_C_V01_ZX_DD_N_240109. It is a android 4.4 modem router. I can install apps and i access to adb and shell without root access.
How i can install openwrt on it?
Nope. That device is not supported by OpenWrt. You can easily check for support by yourself with these two resources:
Firmware Selector
OpenWrt Table of Hardware
If it's not listed, it's not supported.
not supported by openwrt for certain.
not sure if any is keen to pinch headless devices but for android devices you have some options.
ubuntu/debian derived
new(er) android
lineageos
android dev forums
xda-developers.
your build tag points nowhere, try to figure android device name in manufacturer/codename form.