Create flash dump of mtd2 or mtd3 (Image A / Image B):
dd if=/dev/mtd2 of=/tmp/mtd2
Download flash dump from SFP (e. g. using TFTP).
Download header file (rename to 'header') and add it to flash dump:
cat header mtd2 > firmware.upf
Copy software version string from flash dump to header:
dd if=firmware.upf of=firmware.upf bs=1 skip=632 seek=124 count=32 conv=notrunc
Get CRC32 of firmware.upf:
v=$(cat firmware.upf | gzip | tail -c 8 | head -c 4 | hexdump -e '1/4 "%08x"')
Convert CRC32 to binary and write it to header:
echo -e -n "\x${v:0:2}\x${v:2:2}\x${v:4:2}\x${v:6:2}" | dd of=firmware.upf bs=1 seek=104 conv=notrunc
Change extension to .zip and extract.
.img: raw mtd2 flash dump
.upf: with header
1.00 is based on OpenWrt 12.09. Deutsche Telekom (Germany) seems to stick with this branch.
2.50 is based on OpenWrt 14.07. Wind Tre (Italy) upgraded to this branch at the end of 2022.
Both branches are maintained separately, so a specific 1.00 image can have a later build date than a specific 2.50 image.
V1 00(ABVJ 0)b3s (2020-12-23)
V1 00(ABVJ 0)b3v (2021-05-08)
V1 00(ABVJ 1)b1e (2023-07-26)
V2 50(ABVJ 1)b1d (2023-04-21)
@Emmegi2001 The relevant part is:
So just the way you set the speed to 2.5G, you should be able to set it back to the default 1G.