To obtain the latest Arm Trusted Firmware sources you can clone the git repository:
$ git clone https://github.com/ARM-software/arm-trusted-firmware.git
The version of Arm Trusted Firmware included in the Arm Reference Platforms deliverables under the `/arm-tf/' directory is the latest that has been validated on the supported Arm-supplied development platforms, but may not necessarily be the same as the most up-to-date development version.
To forcefully synchronise your workspace's Arm Trusted Firmware sources to the latest version:
$ cd <workspace>/arm-tf/
$ git fetch github
$ git checkout --track github/master
Note that while we expect the latest Linaro software stack deliverables and latest Arm Trusted Firmware development version will always be compatible, this may not actually be the case. Please keep this in mind when attempting to use a more recent version of the Arm Trusted Firmware sources.