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There are two locations in AFS in which we keep our buildroot versionsreleases.

• /afs/slac/g/lcls/package/linuxRT - this locations location seems to be deprecated
• /afs/slac/g/lcls/tftpboot/linuxRT/boot - this seems to be the currently-accepted location

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The example name indicates it is the second release of buildroot (the artifacts) based off the 2019.08 version of buildroot (the tool).  Note that it does not indicate when you built this version.  You may have built it today but you based it off a version of buildroot from 2019 (or whenever).

The "ipxe" directory under "boot" contains file for every machine that boots buildroot.  The filename indicates the machine name.  In that file you will find a line like this:

...

You can modify that line to point at whatever version of buildroot you would like.

Versions

There are many versions that get baked in to buildroot.  There is a BusyBox version, a kernel version, a Preempt RT patch version, user tools versions, and of course a buildroot version.

The version of buildroot (the tool) you download and use defines the BusyBox and kernel versions.  The kernel version defines the Preempt RT version.  So, the buildroot (tool) version is the key to all the versions.