Throw this in terminal:
$ git remote add upstream https://github.com/ORIGINAL_OWNER/ORIGINAL_REPOSITORY.git
Open up the repo's .git/config
.
You should see the following:
[remote "upstream"]
fetch = +refs/heads/*:refs/remotes/upstream/*
url = git@github.com:ORIGINAL_OWNER/ORIGINAL_REPOSITORY.git
Append this at the end:
fetch = +refs/pull/*/head:refs/remotes/upstream/pr/*
It should now look like this:
[remote "upstream"]
fetch = +refs/heads/*:refs/remotes/upstream/*
url = git@github.com:ORIGINAL_OWNER/ORIGINAL_REPOSITORY.git
fetch = +refs/pull/*/head:refs/remotes/upstream/pr/*
Now fetch all the pull requests:
$ git fetch upstream
From https://github.com/ORIGINAL_OWNER/ORIGINAL_REPOSITORY
* [new ref] refs/pull/1/head -> upstream/pr/1
* [new ref] refs/pull/2/head -> upstream/pr/2
...
$ git checkout upstream/pr/2
Voila!
Credits: