TWRP, los procesos de actualización terminaron con ERROR: 7

Cada vez que trato de flashear Lineage OS con TWRP v 3.2.1-0, estoy recibiendo

Updater processes ended with ERROR: 7
Error installing zip file '/sdcard/...n1awifi-signed.zip

Cuando compruebo mi recovery.log

Skipping Digest check: no Digest file found
I:Update binary zip
I:Zip does not contain SELinux file_contexts file in its root.
I:has_legacy_properties: Found legacy property match!
I:Legacy property environment initialized.
Target: samsung/lt03wifiue/lt03wifiue:5.1.1/LMY47X/P600UEUDOK1:user/release-keys
Target: samsung/lt03wifiue/lt03wifiue:5.1.1/LMY47X/P600UEUDOK1:user/release-keys
detected filesystem ext4 for /dev/block/platform/dw_mmc.0/by-name/SYSTEM
detected filesystem ext4 for /dev/block/platform/dw_mmc.0/by-name/SYSTEM
about to run program [/tmp/install/bin/backuptool.sh] with 2 args
Not backing up files from incompatible version: 14.1
run_program: child exited with status 127
about to run program [/tmp/install/bin/otasigcheck.sh] with 1 args
You have an installed system that isn't signed with this build's key, aborting...
run_program: child exited with status 124
script aborted: Can't install this package on top of incompatible data. Please try another package or run a factory reset
Can't install this package on top of incompatible data. Please try another package or run a factory reset
Updater process ended with ERROR: 7

Cómo resuelvo este error He validado que mi TWRP y mi rom (que estoy tratando de flashear) coincide con mi arquitectura (por número de modelo y el resultado de /proc/cpuinfo )