Enable UART pins - GruszekG/nanny GitHub Wiki
1. Go to /boot.
cd /boot
2. Backup the uEnv.txt file.
sudo cp uEnv.txt uEnv.txt.backup
3. Open uEnv.txt with sudo privileges.
sudo nano uEnv.txt
4. Point a specific library from /lib/firmware as overlay address. The part of a final version of uEnv.txt which enables UART4:
...
###U-Boot Overlays### ###Documentation: http://elinux.org/Beagleboard:BeagleBoneBlack_Debian#U-Boot_Overlays ###Master Enable enable_uboot_overlays=1 # UART 4 uboot_overlay_addr0=/lib/firmware/BB-UART4-00A0.dtbo
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