How can I determine what version of the firmware will be installed by running rpi-update, without making any modifications to the installation?


This is from the rpi-update (a bash script in /usr/bin) that shipped in the raspbian 2015-01-31 image, but I do not think it changes that much and it works to give a revision number. The value written to .firmware_revision is from here:

GITREV=$(curl -s ${REPO_API} | awk '{ if ($1 == "\"sha\":") { print substr($2, 2, 40) } }')

$REPO_API is https://api.github.com/repos/Hexxeh/rpi-firmware/git/refs/heads/master, which returns a hunk of json like this:

  "ref": "refs/heads/master",
  "url": "https://api.github.com/repos/Hexxeh/rpi-firmware/git/refs/heads/master",
  "object": {
    "sha": "5b0cbedacf45e111f02d925fa5b1cec9041fb279",
    "type": "commit",
    "url": "https://api.github.com/repos/Hexxeh/rpi-firmware/git/commits/5b0cbedacf45e111f02d925fa5b1cec9041fb279"

This is from git itself, which produces that sha hash. It's sort of obvious from the awk line that's what's being extracted, but to demonstrate, just run:

curl -s https://api.github.com/repos/Hexxeh/rpi-firmware/git/refs/heads/master | awk '{ if ($1 == "\"sha\":") { print substr($2, 2, 40) } }'

I just got back 5b0cbedacf45e111f02d925fa5b1cec9041fb279. So there you go.

  • And what is the firmware version contained in that commit? – Alistair Buxton Apr 28 '15 at 6:31
  • With reference to the number from vcgencmd? Have you found any documentation that claims that is the firmware revision (as opposed to the more conventionally obvious, that it is the vcgencmd version)? This is the number that goes into .firmware_revision, and you can find each one in the repo because it comes from the git commit tag. If there is some other numbering system you are aware of, you should reference it in the question. – goldilocks Apr 28 '15 at 13:20

rpi-update currently defaults to installing the firmware found in the head commit of the master branch of the http://github.com/Hexxeh/rpi-firmware repository. In order to find the build time and version of this (or any) firmware, one can fetch start.elf or start_x.elf and use strings:

strings start.elf | grep VC_BUILD_ID

VC_BUILD_ID_TIME: 14:42:19
VC_BUILD_ID_TIME: Apr 21 2015
VC_BUILD_ID_PLATFORM: raspberrypi_linux
VC_BUILD_ID_VERSION: 2d5ad04b63af4233440c3f7c8587108223201102 (clean)

Note that there will be a few minutes difference between the VC_BUILD_ID_TIME of start.elf and start_x.elf with the same VC_BUILD_ID_VERSION. This is due to them being built one after the other, from the same sources.

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