We purchased an upgrade for our printer a few months ago and I just got around to installing it last week. The upgrade is a prewired control box that contains a Duet 2 WiFi and a Duex expansion board. While setting up the firmware and such I had a difficult time with the Wifi. Sometimes the Wifi would work after resetting the board and sometimes it would not. The Wifi is set to access point mode and works fine when it starts up while other times it shows the WiFi module has been disabled. When it is in the error state M552 commands don't seem to be working and M997 S1 fails to write giving a comm error. At first, I believed it was just the antenna wire being loose because while checking that the connection was secure (gave it a wiggle) the Wifi started working again. The issue has returned after a few restarts.

M552
WiFi module is disabled<LF>ok<LF>
M552 S0
ok<LF>
M552 S2
Turn off the current WiFi mode before selecting a new one<LF>ok<LF>
M552 S-1
WiFi module stopped<LF>ok<LF>
M552 S0
ok<LF>
M552 S2
Turn off the current WiFi mode before selecting a new one<LF>ok<LF>WiFi module disabled - start timed out<LF>
M552 S0
ok<LF>
M552 
WiFi module is being started<LF>ok<LF>WiFi module disabled - start timed out<LF>
M997 S1
T0:24.9 /0.0 T1:24.5 /0.0<LF>Trying to connect at 230400 baud:  failed<LF>Trying to connect at 115200 baud:  failed<LF>Trying to connect at 74880 baud:  failed<LF>Trying to connect at 9600 baud:  failed<LF>Error: Installation failed due to comm write error<LF>ok<LF>
M122
=== Diagnostics ===<LF>RepRapFirmware for Duet 2 WiFi/Ethernet version 3.4.5 (2022-11-30 19:36:12) running on Duet WiFi 1.02 or later + DueX5v0.11<LF>Board ID: 0JD0M-9P6B2-NJ4S8-6JTDG-3SJ6N-1B4QK<LF>Used output buffers: 4 of 26 (26 max)<LF>=== RTOS ===<LF>Static ram: 23836<LF>Dynamic ram: 77032 of which 12 recycled<LF>Never used RAM 8344, free system stack 170 words<LF>Tasks: NETWORK(ready,56.0%,380) HEAT(notifyWait,0.4%,333) Move(notifyWait,0.0%,363) DUEX(notifyWait,0.0%,24) MAIN(running,43.6%,440) IDLE(ready,0.1%,30), total 100.0%<LF>Owned mutexes: USB(MAIN)<LF>=== Platform ===<LF>Last reset 02:56:16 ago, cause: power up<LF>Last software reset at 2023-10-10 15:05, reason: User, GCodes spinning, available RAM 7400, slot 2<LF>Software reset code 0x0003 HFSR 0x00000000 CFSR 0x00000000 ICSR 0x0041f000 BFAR 0xe000ed38 SP 0x00000000 Task MAIN Freestk 0 n/a<LF>Error status: 0x0c<LF>Aux0 errors 0,1,0<LF>Step timer max interval 0<LF>MCU temperature: min 20.0, current 25.5, max 26.5<LF>Supply voltage: min 24.4, current 24.5, max 24.5, under volta[Warning: Maximal number of characters per line exceeded! Check the line break settings in [Terminal > Settings > Text] or increase the limit in [Terminal > Settings > Advanced].]
M115
FIRMWARE_NAME: RepRapFirmware for Duet 2 WiFi/Ethernet FIRMWARE_VERSION: 3.4.5 ELECTRONICS: Duet WiFi 1.02 or later + DueX5v0.11 FIRMWARE_DATE: 2022-11-30 19:36:12<LF>ok<LF>

After going through some of the posts I believe we have a bad module.