I have an LG K20 Plus cell phone. It's stuck in Fastbook.

[Android Central Question]

Have tried taking out battery and holding on/off and volume - still stuck. Please help.

 

[Rukbat]

Fastbook? Or fastboot?

If it boots to fastboot all the time, the Android partition is corrupt and won't boot. You may get some ways of reflashing it without wiping your data at https://forum.xda-developers.com/lg-k20-plus. Some phones can be reflashed without wiping user data - I don't know about LG. (The people there would, and may have a ROM image you can use.)