I am trying to setup a TO with 19.07 from scratch, but when it boots up, uhttpd is not running and is waiting the the openssl step to complete. It stays in the state forever. A workaround seems to be to perform a first boot from 18.06 to get the key file generated and then upgrade to 19.07.
root@OpenWrt:~# ps -w | grep uhttp
3265 root 1220 S /bin/sh /etc/rc.common /etc/rc.d/S50uhttpd boot
3372 root 3568 S /usr/bin/openssl req -x509 -sha256 -outform der -nodes -days 730 -newkey rsa:2048 -keyout /etc/uhttpd.key
4152 root 1064 S grep uhttp
could be that the openssl key generation hangs during maiden boot since there is almost nothing running at that time in the system and thus having a hard time to gather entropy and to generate certificate.