The "lineage-14.1-20180419-UNOFFICIAL-gtel3g" fix refers to a custom ROM build specifically for the Samsung Galaxy Tab E 9.6 (SM-T561)
What is LineageOS 14.1 20180419 Unofficial GTE LTE 3G? lineage14120180419unofficialgtel3g fix
Unlock Your Device's Bootloader: Many devices require a bootloader unlock to install custom ROMs. This process varies by device. The "lineage-14
