Boron bootloader flash issue

I have bought a lot of Boron LTE devices. But I’m having a issue with some of the devices preloaded with version 1.4.2. I’m trying to manually upgrade them to version 1.4.4. But I sometimes run in to an issue with flashing the bootloader over.

particle usb dfu
particle flash --usb boron-system-part1@1.4.4.bin

particle usb listen
particle flash --serial boron-bootloader@1.4.4.bin
particle usb dfu
particle flash --usb boron-softdevice@1.4.4.bin

The error I’m seeing is:
(node:138969) UnhandledPromiseRejectionWarning: unknown message
(node:138969) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag --unhandled-rejections=strict (see (rejection id: 1)
(node:138969) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.