1. First of all, let me state that the official OTA upgrade package can be flashed with third-party REC! And there will be no double clearing! 2. Where should I put the official OTA upgrade package after downloading it? It's in the .OTA folder under the phone's storage directory. When upgrading with a third-party REC, be careful to remove the .zip upgrade package from the .OTA folder, otherwise the files in the .ota will be automatically deleted after the official rec upgrade fails. 3. Can OTA upgrade be cross-version? Yes, the official OTA upgrade will automatically download all upgrade packages to .ota and then flash them one by one. For example, if your version is 0530, then if you upgrade to 0630, you will download two upgrade packages, one 0624 (kernel number 8545) and one 0630 (kernel number 8704). You take out the corresponding flash package and use the third-party REC to upgrade in order! 4. Why does the OTA upgrade fail? The main reason why the OTA upgrade fails is that you have changed the system files, such as flashing a baseband that is not of this version, or flashing the GMS (Google Service Framework) package, which may cause the OTA upgrade to fail! The OTA upgrade package will verify the original system files before updating. If it is found that the signature of the upgrade package script file is different, an error will be reported indicating that the verification failed (when you use a third-party rec to flash the OTA upgrade package, the error will be displayed with detailed information. , which file verification failed) 5. How to solve the problem of OTA upgrade system file verification failure? Two options: 1. Restore the relevant system files to the original version of the ROM 2. Modify the script file in the OTA upgrade package and delete the relevant verification content! The specific operation method is as follows: Open the zip upgrade package, go to the META-INF\com\google\android directory, modify the updater-script file and replace it, such as the picture below: If you get an error when you use a third-party REC to flash the OTA upgrade package, you can Find the corresponding statement in this script and kill it! 6. I don’t think it is true that the OTA upgrade after rooting will fail, errors, etc. To put it bluntly, the OTA upgrade is just writing files to the system partition and replacing system files. The root operation also writes to the system partition. There are just a few files, one is SU in the BIN directory, and the other is an apk program, generally called authorization management (superuser or supersu). Root failure is often because the su file in the bin directory does not match the Linux kernel, causing root failure. fail. Before upgrading ota, you will go to the bin directory to find su to confirm whether the machine has been rooted. If it is rooted, a scary warning will pop up. I think this is just a way for the official to disclaim the responsibility!