[DSi] Freezes on security information

I recently bought a Nintendo DSi that was sold as not working/for parts. When it arrived, I noticed that the Wi-Fi module was missing. I installed the Wi-Fi module from another DSi I had, and the console now boots, but it freezes halfway through the Health & Safety/security information screen.

The Wi-Fi module itself seems to be fine, because the other DSi boots normally with the exact same module installed.

I think the issue might be similar to this other Reddit post:
https://www.reddit.com/r/consolerepair/comments/ic3ih4/nintendo_dsi_health_and_safety_freeze_crash_why/

So far, I've tried:

• Booting while holding A + B to check for Unlaunch.
• Cleaning the Wi-Fi connector with isopropyl alcohol.
• Reseating all the connectors.
• Booting with and without DS cartridges.
• Booting with a clean/empty SD card.
• Inspecting the PCB for corrosion or physical damage. It looks very clean, and I can't see any obvious damage.

Unfortunately, none of that made any difference.

The only thing that has worked so far is using a DS Pico, because it skips that screen completely and allows the console to boot to the Pico menu.

Is there any diagnostic or repair tool that can check the DSi's firmware, NAND, Wi-Fi communication, or other hardware for problems? Or are there any specific components/signals I should check that could cause the console to freeze specifically on the Health & Safety screen?

Any suggestions for further troubleshooting would be greatly appreciated.