at the very beginning of your disk since it carries the partition table (and the SPL) usually
as i said before, i’m neither a fan of manually hacking a half built image nor am i working a lot with these hacked up fastboot bits. you have to ask @ondra, i personally would still go with a properly built image and install it with godd (or build an image that shps a modified godd plus a copy of the emmc image and auto-installs it from usb key/SD card) as i mentioned above …
through the snappy_boot script in your uboot.env
see
