While most developers try to pack in the required partition files with their custom ROM, there are some who release their ROM and recommend using the remaining files like boot, vbmeta, vendor_boot, etc. from the ROM on which it is based.
While in most cases this isn’t a cause of concern, sometimes, if the developer isn’t active in releasing their ROM, then errors like Denying OTA because it is an SPL Downgrade can occur.
If you’re getting this issue, then this guide will be helpful. In this guide, you will get to know how to fix Denying OTA because it is an SPL Downgrade.
How to fix Denying OTA because it is an SPL Downgrade?
Method 1: Find an older version closest to the date
If you’re getting the Denying OTA because it is an SPL Downgrade error, then the first thing you should try is find an older version of the partition files that you flashed in the Fastboot Mode from the base ROM. If you’re not able to find the same version that was in sync with the ROM, at least try to find the partition files from the October build and then try to use the files from the first week of November.
Method 2: Find the latest ROM
Another method to try if you’re getting the Denying OTA because it is an SPL Downgrade error would be to reach out to the ROM developer and request them to update their ROM package to the newest version. This will not only help rectify the issue but it is never recommended that you should use an excessively older build from a security point of view.
Method 3; Use all partition files of the same date
Lastly, you should ensure that all the partition files that you’re using belong to the same release date. Using boot and vendor_boot from 27th November but using dtbo and vbmeta from 21st November isn’t allowed and will likely give you the Denying OTA because it is an SPL Downgrade error.
