AC86U DFS Channels Missing (Canada) Latest Firmware

I recently picked up a AC86U for a relatively good price. I bought it on the recommendation that it had DFS channels available (https://www.duckware.com/tech/wifi-in-the-us.html#routers). After reading a few threads here it seems like it's mainly available on EU or CN versions. But, also saw someone mentioned that it was enabled for US models starting from firmware 384.

I've tried updating the firmware with both official firmware and Merlin but I'm having no success at all...

AC86U DFS Channels Missing (Canada) Latest Firmware