Rajganesh

Thanks added IntelBluetoothFirmware.kext which fixed the Bluetooth issue. Overall now this configuration looks stable. Thanks for your support. 

@davidfrei7as & @Jake Lo, Thanks, I was able to use David's EFI and perform an uprade from BigSur to Monterey. Overall it was a smooth process but for below few issues.

1. Wi-Fi did not work in Monterey, which was working in BigSur. Fixed it by applying the latest stable airportitlwm.kext (which was not available in David's EFI)
2. Bluetooth is not working in Monterey, which was working fine in BigSur. I don't remember applying any kext for bluetooth in BigSur, not sure what is missing now?
3. System Preference is laggy in Montery (particularly Trackpad & Bluetooth settings are not opening). Any inputs? 

Thank you, will try an upgrade this weekend. 

@davidfrei7as

Do you think this EFI will work for upgrade from BigSur to Monterey? 

@Jorge1964

Any updates on this? Have you resolved the boot loop? I am also planning to update for my Latitude 3400 to Monterey, need your confirmation before I can try