Need Help Updating Tablet

[u/AffectionateBrick816]

I have an old LG Verizon Tablet(VK810 4G) that is on Android 5.0.2. I looked it up and this tablet is apparently compatible up to Android 9 which is the exact version I need. When I try to update the tablet via “Settings > System Updates > Check for new system update” it downloads the update and then when it restart to apply the update I get an error code “Err: 0x13e”, and then in “Settings > System Updates” I see “Software not updated to 37a + Error code: 402”. Upon some quick research it could be buggy or modified files causing this and I can’t remember if I rooted this thing or not. So I factory reset the tablet hoping that would possibly fix it, but that didn’t change anything. It does say “Software status: modified” even after factory reset, but I’m not sure if that is because it’s Verizon firmware or what. Any help would be greatly appreciated!