So, I purchased RT-AC88U here in China.
(Not sure if this post should be here or in the Merlin section, but here goes).....
Set it up with its delivered firmware and worked fine.
Changed the firmware to Merlin 380.58 and set it up again. Working ok.
Then I changed the region from China (the default) to Europe.
Router rebooted and worked fine on wired LAN.
But, as soon as a wifi client attempts to connect, router crashes and then reboots. This happens on 2.4 or 5 gig and with different clients - iPhone, android phone or windoze 10 laptop.
Changed region back to China. Router rebooted. Tried wifi again and works without issue.
Bootloader is 3.0.0.0
I have not yet changed the firmware again. I'm considering what to do.
Would appreciate any suggestions.