[LEDE-DEV] ImageBuilder generated image does not create LED entries in /etc/config/system on first boot, why?

[Laurent GUERBY]

Hi,

On a 841N v11 on current LEDE git with patch from (1) I'm trying to
solve a puzzle:
- when doing "make" the generated image in 
bin/targets/ar71xx/generic/lede-ar71xx-generic-tl-wr841-v11-squashfs-sysupgrade.bin
does create on first boot /etc/config/system 'led' entries and so
the LED work as expected
- whe using a script (2) based on the imagebuilder generated by the same
"make" build (menuconfig activated)
bin/targets/ar71xx/generic/LEDE-ImageBuilder-ar71xx-generic.Linux-x86_64.tar.bz2
the image works but /etc/config/system is not populated with 'led'
entries on first boot (or second boot I tried) so the LAN/WAN LED stay
off (only power LED is on). If I populate manually /etc/config/system
all works.

I couldn't find what script running on the router which generates
the /etc/config/system led entries on first boot (where to look to debug
this issue), I assume something is missing flag or package or kernel
module in my imagebuilder (or make menuconfig) setup but I'm not able to
find it. I did not have this issue with older versions of OpenWRT
imagebuilder.

Any help appreciated,

Sincerely,

Laurent

(1) https://github.com/lede-project/source/pull/64
(2)
https://chiliproject.tetaneutral.net/projects/git-tetaneutral-net/repository/openwrt-tools/revisions/master/entry/quick_841n_ttn_lede.sh