Snagboot, Bootlin’s vendor-agnostic recovery tool for embedded platforms, has been under continued development since its first release in May 2023. Let’s take a look at the main changes brought by version 1.3, published just a few days ago.
Passing USB device paths
Both snagrecover and snagflash previously relied on USB vendor ID:product ID addresses to find recovery devices exposed by boards. This was problematic in the case where two boards with the same vendor and product IDs had to be recovered or reflashed simultaneously. To solve this issue, we added the ability for snagrecover and snagflash to use USB paths of the form bus:port1-port2-... instead.
The main challenge we faced while implementing this feature was integration into the NXP i.MX recovery process. In Snagboot 1.2, i.MX recovery relied on the Python ctypes bindings to the hidapi library. These bindings did not allow searching for an HID device using bus/port paths. This, and other issues we encountered with hidapi bindings led us to drop them entirely and reimplement a partial HID library inside the Snagboot codebase.
i.MX53 support
Martin Fuzzey contributed a set of changes to snagrecover that added support for the i.MX53 family of SoCs. A few changes to the protocol layer of Snagboot were necessary since these SoCs used a raw USB device instead of an HID device.
Improvements to the AM335x setup script
Recovering AM335x platforms with Snagboot requires setting up a recovery shell using a special helper script. We’ve cleaned up the syntax and some of the logic of this script to bring it closer to POSIX compatibility and allow non-Bash shells such as Fish shell to run it successfully.
These are the main changes brought by v1.3. If you’re curious to see more, you can view the full changelog here. Thank you to all the people who contributed to this release!