OTA is the mechanism by which OEMs remotely update the system partition of a device:
- Android 5.0 and later versions use block OTA updates to ensure that each device uses the exact same partition. Instead of comparing individual files and computing binary patches, block OTA handles the entire partition as one file and computes a single binary patch, ensuring the resultant partition contains exactly the intended bits. This allows the device system image to achieve the same state via fastboot or OTA.
- Android 4.4 and earlier versions used file OTA updates, which ensured devices contained similar file contents, permissions, and modes, but allowed metadata such as timestamps and the layout of the underlying storage to vary between devices based on the update method.
File based OTA update in not available beyond AOSP Android 5.0. Sometimes it is require to provide few configuration files along with OTA.
We have solution that provide file based OTA supports along with block-based OTA file. This solution requires to add few codes in AOSP recovery files and few changes in AOSP code.
https://prabhusystemtech.com/2022/08/27/file-based-ota-update-along-with-block-based-ota/