Some folks may hit an error in mkinitfs when updating that the dtb for their device cannot be found. This is caused by a shell bug in boot-deploy.
This issue affects Android devices which boot using an Android boot image, and potentially other devicetree-based devices.
This is fixed in boot-deploy 0.10.2 which can be found in this mr.
To fix, either wait until the new package is available before updating, or install it now with mrtest.
If your device is unbootable, you'll need to either build a new boot.img or download the latest from the downloads page for your device. Once booted again, ensure your device is up to date and then run sudo mkinitfs to regenerate the boot image.