the_hamster wrote Had the same problem, and discussed in this thread: http://forum.tp-link.com/showthread.php?100834-Erroneously-installed-EU-firmware-version-now-can-t-install-correct-US-upgrades...

vieldcs wrote Hi Luowilliam,There is no way to downgrade the firmware once it has updated to the US version, for the wifi unstable issue , have you tried to change channel and channel width?How about...

Curious did you ever find out how to overwrite CA version of firmware back? I'm in the same boat. I noticed the WIFI is very unstable after the router got the US firmware.