The Thistle Update Client relies on external Shell scripts to perform the Bootloader integration. Two simple scripts are required in order to inform the Update Client - one is required to tell the bootloader to attempt a boot on the newly updated partition, and another one to confirm that the boot was successful (latch-in update). We provide example for Raspberry Pi under the integration page.
For any bootloader setup supported by the Thistle Update Client, it is required to have 2 partitions available, that will be used as root filesystem alternatively.