Flashtool Interface for ECID

It is possible to use the flashtool interface to specify an ECID for a given partition.

This feature allows for a debug version of a specific partition software to be compiled and signed for a given target device. In this case, the software will only be allowed to be run on the target that the ECID in the configuration file matches.

As an example, if you want to debug an issue in the kernel on a specific target, you can compile and sign the binary. Then in the flashing configuration, you would add the ECID of the target that you want to run this on.

With this entry in the kernel partition, once the images are created, this partition will only be allowed to run on the target that it matches. Since the images are signed even if someone tries to change the ECID in the header, the signature will not match and the kernel will not boot, at which point the system will default to recovery mode.

To get the ECID of the board, you need to flash the board at least once. Then go through the output logs. Both the BR_CID and the ECID of the board is given and should look like:

Target BR_CID: 0xa80219116420f0c12400000011ff8180
Target ECID: 0x16420f0c12400000011ff8180

Where the ECID is the last 100 bits of the BR_CID.