Strange behavior of bluetooth chip

[Vitaly Shevtsov <shev.vt1984%gmail.com@localhost>]

Hello.

My wireless chip is defined as: Intel Wireless AC 9260 (different
network, version 0x29) on pci1 dev 0, function 0 not configured.

When booting the system I always got an error:
CommanComplete opcode failed (003|0003) (status=0x01).

When I tried to manually raise the interface via `btconfig ubt0 up`, I
received the error:
btconfig: SIOCSBTFLAGS: Resource temporarily unavailable.

I decided that my chip was not working until I reboot into Windows and
then back into NetBSD, after which the bluetooth worked.

How so? :) I suspect that the firmware is missing and Windows uploads
it. If so then I don't understand how it survives the reboot.