After some poking around, going back to boot partition ada0s2a, rebooting, problem is the same.
I had made a copy of / on some spare space on the SSD. I changed /usr/local/share/pfSense/pkg/repo/pfSense-repo.conf to point to url: "pkg+https://pkg.pfsense.org/pfSense_v2_3_5_xxx and I did a pkg-static bootstrap -f and it seems the problems are solved:
pkg is working nginx is starting at boot timeHow can I make sure nothing else is messed up in my installation?
Thanks in advance,
Olivier