See bug: https://github.com/openwrt/openwrt/issues/9283
uclient-fetch with libustream-wolfssl installed cannot fetch an https page with an encrypted certificate, but curl compiled with the same version of libwolfssl can.
The same problem occurs with the current sanpshot - uclient-fetch cannot download the ex. https://letsencrypt.org page.
# wget -O /dev/null https://letsencrypt.org/
Downloading 'https://letsencrypt.org/'
Connecting to 164.90.180.144:443
Connection error: Invalid SSL certificate
Bug in libustream-wolfssl?