ZST39 Firmware 1.6 (7.23.2) won't update because of bootloader

Has anyone updated their controller to v1.6? File ZST39_SDK_7.23.2_US-LR_V01R60.gbl. It’s on the Zooz website, but not listed on the revision page.

Attempting to update, it immediately fails with this error below. The bootloader is aborting it, so I tried a soft-reset to see if it was in a bad state. But that didn’t help.

I don’t recall any other steps that should be needed. Any ideas?

I just did mine today using the update button in HA. Worked without an issue with the same gbl file name