Hi Fellows!
Some feedback of recent progress: I bought and received the new wifi card (
https://www.aliexpress.com/item/Bro.../1390948701.html?spm=2114.13010608.0.0.5NHQ5i) and works flawlessly from first boot with the Broadcom kexts found in this thread. Swapping out was easy, only had to fiddle around a little with one of the radio cables, as we get less space because of a small metal part on the card, that is missing from the original HP one. BT can see my iPhone 6S, but cannot connect to it, other BT devices are okay (tested with Oneplus One). The module cannot be turned off. Connection speed is about 150KB/s.
Pressing the wifi radio button disables wifi and cannot be turned on again, no matter how long I wait. Rebuilding cache solves it again.
The machine dual boots W10 from HDD and El Capitan from SSD. It was tricky at times, but now it is perfect. I use native UEFI without CSM, because it looked like, that resolution is only perfect that way, but I will experiment more.
Weird (?) thing: doesn't matter if I use the FakeSMC sensor kexts or not, I can only see temp readings of the SSD, HDD and battery percentage in HWmonitor app. Is it by design RehabMan or just doesn't work with my setup? (Rebuilding cache didn't change anything)
Cheers