does Lineage wiki offer a firmware upgrade solution for this device ?
if answers to 3 and 4 are no, you will have to install latest available full Stock OS (relative to the android version of the /e/ build you want to install → not higher), then reinstall /e/OS from scratch.
if answer to 3 is yes, you can have a go to dirty upgrade /e/OS.
if answer to 4 is yes, you can have a go for dirty upgrade the firmware, then dirty upgrade /e/OS !
download the file, go to “→ settings → system updater” and use the feature called “locale update” (if you have it in the “3 dot menu” at top right of the screen).
or
download the file, boot the phone into the recovery mode and use “apply update” then “from internal storage” (if your “recovery mode” have the feature).
or
download the file on a SDcard, boot the phone into the recovery mode and use “apply update” then “from External SDcard” (if your “recovery mode” have the feature).
or
Universal Method, download the file on a computer, boot the phone into the recovery mode and use “apply update” then “from ADB” :
download the latest /e/OS build for your device
(put it into the platform-tools folder)
it must be named like e-3.2-a15-20251023539369-community-instantnoodle.zip
if you found something named like IMG-e-3.2-a15-20251022539003-official-FP6.zip
use the right clic to copy the link, paste it in the adress bar of your browser, remove the 4 IMG- carracters and press enter to download e-3.2-a15-20251022539003-official-FP6.zip
On the computer the sideloading shows progress as a percentage figure that will stop at 47%. The phone will still be installing though (even though it might feel like nothing is happening sometimes!) and you can expect to see the following screens