please check the file board/recalbox/copy-recalbox-archives.sh
line 159, the command genimage is building the image.
from the config output/images/genimage.cfg :
image boot.vfat {
vfat {
extraargs = "-F 32 -n RECALBOX"
file boot/linux { image = 'boot/linux' }
file boot/uInitrd { image = 'boot/uInitrd' }
file boot/recalbox { image = 'boot/recalbox' }
file boot/exynos5422-odroidxu3.dtb { image = 'boot/exynos5422-odroidxu3.dtb' }
file boot.ini { image = 'boot.ini' }
file recalbox-boot.conf { image = 'recalbox-boot.conf' }
}
size = 1200M
}
image batocera.img {
hdimage {
}
partition vfat {
partition-type = 0xC
image = "boot.vfat"
offset = 646656
}
}
i've done this file. there is possibly an option to add for some case.
you should check the genimage documentation : https://github.com/vivien/genimage
do you have genimage installed on your computer ? on mine, no, it's using the genimage compiled for batocera, however, the script seems it doesn't use ${BR....} so, maybe, it's not using the correct genimage in your case.