Windows 10 (10.0.18362 Build 18362) was the last build where my Bluetooth 4.0 device worked with a dongle worked on my DELL Latitude E6420.
Windows 10 Update (10.0.19044 Build 19044), also known as "Feature update to Windows 10, version 21H2", "Successfully installed on 5/14/2022". However, Bluetooth audio fails with driver, "Broadcom BCM20702 Bluetooth 4.0 USB Device". The audio sounds garbled and pulsating. Attempts to disconnect and reconnect Bluetooth devices in the Windows Bluetooth Settings do not function properly.
I have attempted other updates with 1903/19H1, 1909/19H2, 20H1, 20H2, 21H1. I am not sure that Microsoft will have another update. Microsoft appears to have removed specific information that from my Microsoft Update History. All of these versions appeared to have the Bluetooth problem. Device Manager also has problems. I attempt to disable and reenable Bluetooth devices in Device Manager and the screen in Device Manager becomes greyed and Device Manager reports "Not Responding"). I also noted that Device Manager would show as updated but the Bluetooth Settings was showing the old driver.
Microsoft updated from Broadcom BCM920702 to Broadcom BCM20702, for a Bluetooth 4.0 USB device. With the failure each time, I made a move to restore the last major update in Recovery or I used a restore point to recover Windows 10 Update (10.0.18362 Build 18362).
I further went into the registry and disabled automatic updates which may be a group policy setting.
See the following registry key: 'Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate\AU'
See: https://smallbusiness.chron.com/turn-off-computer-updates-51365.html
My move to try this new update was motivated by Oracle's VirtualBox which I updated to either version '6.1.32' or version '6.1.34'. When I updated VirtualBox, Oracle updated Windows 10 Update (10.0.18362 Build 18362) with Broadcom driver "Broadcom BCM20702 Bluetooth 4.0 USB Device" and it functioned correctly. Device Manager reported this new Bluetooth driver correctly. However, Bluetooth Settings was still reporting the old Bluetooth Driver. So, this is a Microsoft bug. Recently and subsequently, I tried to access the internet from my DELL Latitude E6420 laptop by tethering Bluetooth to my smartphone, a Razer Phone 2 with Android 9. When I enabled Bluetooth tethering on my phone and then connected to the access point using Bluetooth in Windows 10, my driver information suddenly updated in the Windows 10 Bluetooth Settings to the 'BCM20702' or 'BCM20702A0' driver nomenclature. I cannot recall if the VirtualBox Bluetooth driver was 'BCM20702' or 'BCM20702A0' before the update. I was very happy to see this newer Bluetooth driver operating correctly on my DELL Latitude E6420.
Note: I found this reference for a Lenovo Bluetooth driver which lists a Windows 7 driver only as 'BCM20702' so there might be a difference.
See https://pcsupport.lenovo.com/us/en/products/laptops-and-netbooks/thinkpad-x-series-laptops/thinkpad-x140e/downloads/ds036712
Even though I disabled automatic updates, Microsoft attempted an updated to my computer on May 3rd, 2022. I think that was a major update to Windows 10 21H2 which failed. Yesterday, May 13th, 2022, I got a blue screen telling me that Windows was ready to update which I chose to delay. My concern then was that the disabled auto-update feature was not working as intended. Maybe the failure in the update on 05/03/2022 was due to my disabling automatic updates. And maybe, the update I was receiving was a security update instead. Anyway, this motivated me to look at this issue again. I decided to re-enable Microsoft Updates in the registry. And, I decided to update Windows 10 to Windows 10 (10.0.19044 Build 19044) or 21H2 from Windows 10 Update (10.0.18362 Build 18362).
I have tried to update Microsoft Windows 10 many times now from Windows 10 Update (10.0.18362 Build 18362) without success. If I restore this update, I am not sure if I can reload it again. And, at the same time, I do not want to lose Bluetooth functionality. It appears that a restore might be my only option. If all of the prior Microsoft Windows 10 Updates from Windows 10 Update (10.0.18362 Build 18362), Microsoft updated the Bluetooth driver and it failed. I wonder what would happen if I uninstalled the driver and reinstalled VirtualBox 6.1.32 or 6.1.34 which it might reload the BCM20702 driver which worked on Windows 10 Update (10.0.18362 Build 18362) assuming their is a difference in the version of the BCM20702 driver, possibly 'BCM20702' versus 'BCM20702A0'. Maybe Microsoft is installing the wrong driver for the chipset on my laptop or the wrong driver for the Bluetooth USB dongle I have in the USB port.
My Conclusion: Since VirtualBox successfully updated my Bluetooth driver from Broadcom BCM920702 to Broadcom BCM20702 or BCM20702A0 while running Windows 10 Update (10.0.18362 Build 18362) and it functioned correctly, I think Microsoft is loading the wrong version of driver BCM20702 / BCM20702A0 as compared to what VirtualBox loaded, or Microsoft has some bugs in their Bluetooth software which appeared just after Windows 10 Update (10.0.18362 Build 18362). Whatever Microsoft did, overrode the BCM20702 driver which was functioning correctly on my computer. Microsoft Bluetooth Settings ("Bluetooth and other devices') currently shows my driver as 'BCM20702A0', and underneath that it says, "Driver error".
My System Information
OS Name Microsoft Windows 10 Pro
Version 10.0.19044 Build 19044
OS Manufacturer Microsoft Corporation
System Manufacturer Dell Inc.
System Model Latitude E6420
System Type x64-based PC
Processor Intel(R) Core(TM) i7-2640M CPU @ 2.80GHz, 2801 Mhz, 2 Core(s), 4 Logical Processor(s)
BIOS Version/Date Dell Inc. A24, 5/12/2017
SMBIOS Version 2.6
Embedded Controller Version 255.255
BIOS Mode Legacy
BaseBoard Manufacturer Dell Inc.
BaseBoard Product 032T9K
BaseBoard Version A02
Platform Role Mobile
Secure Boot State Unsupported
PCR7 Configuration Binding Not Possible
Windows Directory C:\WINDOWS
System Directory C:\WINDOWS\system32
Boot Device \Device\HarddiskVolume1
Locale United States
Hardware Abstraction Layer Version = "10.0.19041.1566"
Time Zone Central Daylight Time
Installed Physical Memory (RAM) 16.0 GB
Total Physical Memory 15.9 GB
Available Physical Memory 8.80 GB
Total Virtual Memory 31.9 GB
Available Virtual Memory 24.3 GB
Page File Space 16.0 GB
Page File C:\pagefile.sys
Kernel DMA Protection Off
Virtualization-based security Running
Virtualization-based security Required Security Properties
Virtualization-based security Available Security Properties Base Virtualization Support, DMA Protection
Virtualization-based security Services Configured
Virtualization-based security Services Running
Device Encryption Support Reasons for failed automatic device encryption: TPM is not usable, PCR7 binding is not supported, Hardware Security Test Interface failed and device is not Modern Standby, Un-allowed DMA capable bus/device(s) detected, TPM is not usable
A hypervisor has been detected. Features required for Hyper-V will not be displayed.
Summary: This problem for my computer extends back to 2019, maybe 2020, when trying to update Windows 10 Professional (10.0.18362 Build 18362) to 19H1, which has now failed on 19H2, 20H1, 20H2, 21H1 and now 21H2. Uninstalling the Bluetooth driver and loading Oracle VirtualBox 6.1.32 or 6.1.34 may get your Bluetooth working again with Bluetooth driver BCM20702 or BCM20702A0. I have a Bluetooth dongle, so I am not sure this is a dongle only problem, but it could be. I loaded Oracle VirtualBox 6.1.32 and/or 6.1.34 under Windows 10 Professional (10.0.18362 Build 18362) and it prompted me to update my Bluetooth driver from Broadcom BCM920702 to Broadcom BCM20702 or BCM20702A0. And, that Bluetooth driver upgrade worked. They question is why? Trying the VirtualBox installation approach could serve as a patch to the problem. I may prove that Microsoft is loading the wrong variant of the Bluetooth driver Broadcom BCM20702 or BCM20702A0, or that other design and coding changes have created bugs in Microsoft Windows 10 after version Windows 10 Professional (10.0.18362 Build 18362) .