Solvedrpi update Failed to down update for rpi-update

' !!! Failed to download update for rpi-update!
!!! Make sure you have ca-certificates installed and that the time is set correctly

I have read the readme. I made sure ca-certificates was installed, even did a dpkg reconfigure.
Made sure time was correct with the ntpupdate.

Tried alternative steps cloning the repo. Same SSL Cert error.

-k and --insecure did nothing to prevent it

I think this is an issue with the curl package on the retropie and/or rasbian jessie images. I have the same problem, and a generic curl --head https://github.com/ fails with a certificate validation error.

Meanwhile curl --cacert /etc/ssl/certs/ca-certificates.crt --head https://github.com/ succeeds, so there's something wrong with the default curl path.

Using the corresponding environment variable I can work around the issue

sudo CURL_CA_BUNDLE=/etc/ssl/certs/ca-certificates.crt rpi-update

FYI, raw.githubusercontent.com is blocked in mainland China.

sudo UPDATE_SELF=0 rpi-update to skip self update or edit /etc/hosts manually to workaround DNS pollution.

I was able to make some progress by editing rpi-update and adding -k to every curl command. Then I realized when I ran rpi-update it overwrote my changes.

I then discovered this gem 'sudo UPDATE_SELF=0 ./rpi-update'

Seems to be running fine currently.