https://forum.xda-developers.com/t/lg-exalt-lte-and-kyocera-4g-flip-phones-app-apk-install-hack.4050399/post-87645377Never tried but pretty detailed.
If you don't get what's going on here and you just want a full guide, here are the instructions in full:
You have an apk file that you want to put on your flip phone, but it's not working because you don't have enough permissions. Here's what to do:
Download an APK file of the app you want (In my experience apkpure.com has a good selection)
Get APK editor by going to
https://apkeditorpro.com/apk-editor-pro-for-pc/ and following the instructions
Open Bluestacks
On the homescreen, click system apps and then media manager
Click on Import from Windows on the left, and then select your apk
Click the Home Icon in the bottom-right corner
Open APK editor
Click APK file
You could either search for your file on bottom, or find it under /storage/emulated/0/DCIM/SharedFolder
Click Common edit
Under package name, add in com.android.cts.whatever's-at-the-end-of-what-was-there-originaly and save
Click the windows icon (under the home icon) in the bottom-left corner and hit Media Manager
On the left pane hit explore
Go to ApkEditor -> tmp
Click and hold on your file
On top click Export to Windows, save it where you want it, and you're done! You could now install your app on a flip phone!
If you need help installing the app, check out
https://www.apps4flip.com/installation/If you just want me to do it for you, you could email me at fliphonebochur@gmail.com
You're Welcome!