As imilicivic has stated, you have to change the security protocol on your WiFi router to lowly old WPA (or dual WPA/WPA2 if you have that option). You will then have no issues for your Roam 2 / Bolt 2 etc updating. Also needs 2.4 Ghz band but if you have the dual band set to 2.4 ghz / 5 Ghz you will be fine.
Why Wahoo would be using a chip that’s limited to WPA (“Wi-Fi Protected Access”) only I have no idea. The WPA security protocol was introduced in 2003 so more than 20 yr old now. WPA2 was introduced not long after but is significantly more secure and since then WPA3 has introduced stronger encryptions. Basically, WPA is no longer considered secure with TKIP vulnerabilities that allow WPA to be exploited with modern tools and techniques and in fact many modern devices will not work with WPA. Except your Wahoo of course! 
Since I wasn’t prepared to have my home network open with WPA, I set up a separate WiFi network on my mesh router just for my Wahoo Roam 2 connect to and set the security protocol to WPA/WPA2 and the firmware updates work fine. I don’t use that network for anything else. I
I’ve left my main home network on WPA2 – I’d prefer to switch it to the WPA3 option but I have a few devices that won’t work with WPA3 either.