geonet_wrap_shb wrote lifetime 0x83, commented as about 60 s. The field
holds the multiplier in its upper six bits and the base in the lower two
(50 ms, 1 s, 10 s, 100 s), so 0x83 is 32 x 100 s = 3200 s. That is over
the 600 s itsGnMaxPacketLifetime a sender may use at all; vanetza
refuses to send such a packet. The byte arrived with the Phase 03 commit
as a placeholder and was never checked against the encoding.
For a single-hop CAM this is non-compliance rather than a functional
fault: nothing stores or forwards an SHB packet, so no receiver acts on
the value, and no dropped CAM was ever traced to it.
0x05 (1 x 1 s) is what every other station in
its-g5-receiver-firmware/recordings sends its CAMs with; the recorded
GeoBroadcast DENMs use 0x79 (30 s). Changed in obu-cam-transmistter's
copy as well. Both firmwares build (IDF 6.1 and 5.5.4), and the
disassembled geonet_wrap_shb of each stores 0x05. Not yet seen on air:
the production OBU still runs the 2026-09-10 build, and the on-air
check is listed in TODO.md.
Ashin Walpola
8871708a98