OK I aligned my FW:
define Device/wlr-4100v1002
DTS := WLR-4100v1002
$(Device/dsa-migration)
BLOCKSIZE := 4k
IMAGE_SIZE := 7244k
IMAGES += factory.dlf
IMAGE/factory.dlf := $$(sysupgrade_bin) | check-size $$$$(IMAGE_SIZE) | \
senao-header -r 0x0222 -p 0x104A -t 2
DEVICE_TITLE := Sitecom WLR-4100 v1 002
DEVICE_PACKAGES := kmod-usb-core kmod-usb-ohci kmod-usb2 swconfig
endef
TARGET_DEVICES += wlr-4100v1002
Leading to this *.dlf (senao-header -r 0x0222 -p 0x104A -t 2)
$ hexdump openwrt-ramips-mt7620-wlr-4100v1002-squashfs-factory.dlf -n 48 -C
00000000 00 00 00 00 00 00 02 22 00 00 10 4a 31 32 33 00 |......."...J123.|
00000010 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 02 |................|
00000020 00 39 80 04 00 00 00 00 26 f8 99 40 0b 79 6e fa |.9......&..@.yn.|
to the Sitecom:
$ hexdump -n 48 -C WLR-4100v1002-V1-4-1-24.dlf
00000000 00 00 00 00 00 00 02 22 00 00 10 4a 31 32 33 00 |......."...J123.|
00000010 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 02 |................|
00000020 00 50 00 20 00 00 00 00 0a 87 d5 da f4 0e 29 72 |.P. ..........)r|