[One (M8) Android Development] buddwm:
Ok...so I am beginning to doubt this is firmware related. I extracted the wcnss.img from the latest GPE firmware so that I could flash only the wifi chipset without screwing with the other stuff. It updates fine, and wifi still works on 2.4GHz, but I still have the exact same issue on 5GHz. Here is a logcat of what is happening when I try to connect to my 5GHz network (SpeedyUnder is the SSID):

01-15 10:12:50.130 4023 4023 I wpa_supplicant: wlan0: CTRL-EVENT-SSID-REENABLED id=2 ssid="SpeedyUnder"
01-15 10:12:50.135 4023 4023 I wpa_supplicant: wlan0: Trying to associate with SSID 'SpeedyUnder'
01-15 10:12:50.145 833 986 D WifiStateMachine: shouldSwitchNetwork txSuccessRate=1.52 rxSuccessRate=1.28 delta 1000 -> 1000
01-15 10:12:50.146 833 986 D WifiStateMachine: ConnectModeState SSID state=re-enabled nid=2 [id=2 ssid="SpeedyUnder"]
01-15 10:12:50.146 833 986 E WifiConfigStore: Ignoring SSID re-enabled from supplicant: "SpeedyUnder"-NONE had autoJoinStatus=0 self added false ephemeral false
01-15 10:12:50.152 833 986 D WifiStateMachine: CMD_AUTO_CONNECT sup state ScanState my state DisconnectedState nid=2 roam=3
01-15 10:12:50.152 833 986 E WifiConfigStore: saveWifiConfigBSSID Setting BSSID for "SpeedyUnder"-NONE to any
01-15 10:12:50.152 833 986 E wifi_gbk2utf: g_pItemList is NULL
01-15 10:12:50.171 833 986 D WifiStateMachine: CMD_AUTO_CONNECT will save config -> "SpeedyUnder" nid=2
01-15 10:12:50.207 833 986 D WifiStateMachine: CMD_AUTO_CONNECT did save config -> nid=2
01-15 10:12:50.208 4023 4023 I wpa_supplicant: wlan0: CTRL-EVENT-ASSOC-REJECT bssid=20:4e:7f:91:ae:52 status_code=1
01-15 10:12:50.209 4023 4023 I wpa_supplicant: wlan0: CTRL-EVENT-SSID-TEMP-DISABLED id=2 ssid="SpeedyUnder" auth_failures=2 duration=20 reason=CONN_FAILED
01-15 10:12:50.212 4023 4023 I wpa_supplicant: wlan0: CTRL-EVENT-SSID-REENABLED id=2 ssid="SpeedyUnder"
01-15 10:12:50.215 4023 4023 I wpa_supplicant: wlan0: Trying to associate with SSID 'SpeedyUnder'
01-15 10:12:50.228 833 986 D WifiStateMachine: ConnectModeState SSID state=temp-disabled nid=2 [id=2 ssid="SpeedyUnder" auth_failures=2 duration=20 reason=CONN_FAILED]
01-15 10:12:50.228 833 986 E WifiConfigStore: SSID temp disabled for "SpeedyUnder"-NONE had autoJoinStatus=0 self added false ephemeral false
01-15 10:12:50.228 833 986 E WifiConfigStore: message=id=2 ssid="SpeedyUnder" auth_failures=2 duration=20 reason=CONN_FAILED

I turned off any security measures on the 5GHz network to rule out any sort of password/auth issue (except for MAC filtering which I don't want to disable), yet I still cannot connect to it. If I go back to a GPE rom or a Sense rom, or even CM 12.1, I can connect to a 5GHz network without issue.

I should also point out that I tried various firmware files to rule out the one GPE version that I was using. I even tried the latest TMobile wcnss.img from the 4.20.531.5 version. Not sure what else I can do. The ONLY thing I have enabled on the 5GHz network that I didn't turn off is MAC filtering, and I'd rather not disable that as I'll lose my MAC address list. But again, that shouldn't cause it to not work as it works fine on other ROMs.

Not expecting a solution or anything, just thought I'd report the details, but if anyone has ideas I am open to suggestions.

EDIT: More details from dmesg if it helps:

[ 429.071441] c0 3918 wlan: [3918:E :PE ] limProcessAuthFrame: 1351: received Auth frame from peer with failure code 1 20:4e:7f:91:ae:52
[ 429.071495] c0 3918 wlan: [3918:E :PE ] limProcessMlmAuthCnf: 625: Auth Failure occurred.
[ 429.085738] c0 3918 wlan: connection failed with 20:4e:7f:91:ae:52 reason:3 and Status:7
[ 429.085844] c0 3918 wlan: connection failed with 20:4e:7f:91:ae:52 reason:1 and Status:9
[ 429.085882] c0 3918 wlan: [3918:E :HDD] hdd_AssociationCompletionHandler: send connect failure to nl80211: for bssid 20:4e:7f:91:ae:52 reason:1 and Status:9