Error 238 prevents update of Darter Pro

[Chem0metrix]

Distribution (run cat /etc/os-release):
Pop!_OS 19.10

Issue/Bug Description:

Running Pop!_OS 19.10 on a Darter Pro with 1.07.04 firmware. All external devices have been disconnected as per System76's instructions.

On starting the firmware update application, I'm able to shut the system and reboot in preparation for the update. On attempting to start the flash write operation to update the firmware, the following error is generated:

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GbE Region does not exist.

Error 238: The host CPU does not have write access to the target flash area. To enable write access for this operation you must modify the descriptor settings to give the host access to this region.

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Could someone help explain how to modify said descriptor?