$ git remote add upstream [email protected]:mbedmicro/mbed.git
$ git fetch upstream
$ git merge upstream/master
$ git push
$ git remote add xxx_work [email protected]:mbedmicro/mbed_private_xxx.git
[privete repo] You need to have the latest from mbed – master and then create a new remote (this is the URL of the new repo). Then push from the current mbed – master to the new –remote master.
[pull request from private repo] I had to merge into my public repo using a branch and then make the pull request to mbedmicro mbed master