Bluetooth works in 4.19 but not on 5.10 reboot

beaka

Hi, I have a z8350 tablet and am trying to get it working to the stage of bluetooth and power monitor both functional. I installed Debian 10 with kernel 4.19 and the broadcom bluetooth worked, but no battery monitor as no axp288 capability. I then ibstalled kernel 5.10 from backports and the battery monitor works but not bluetooth on same configuration. If I reboot in 4.19 bluetooth works again?
It is a Infinity One tablet with Broadcom 43340/1 wifi bluetooth combo.
I cannot find any documentation requiring changes to bluetooth configuration when upping to 5.10 and dmesg looks similar for both kernels ( I cant seem to post the dmesg's here) so my questions are:
Is there a requirement to change/reconfigure bluetooth when going from kernel 4.19 to 5.10?
Is there any extra/less modules/kernel configs required between kernel versions?
What do I need to do to dive deeper into finding the problem on my own?