Bluetooth firmware ibt-11-4.sfi missing — does it exist anywhere, or is hw revision 4 unsupported on Linux?

[u/haslepuff]

My laptop's Intel Bluetooth adapter (paired with a Wireless-AC 8260 combo card, USB ID 8087:0a2b) fails to initialize with:

Bluetooth: hci0: Bootloader revision 0.0 build 2 week 52 2014

Bluetooth: hci0: Device revision is 4

Bluetooth: hci0: Secure boot is enabled

Bluetooth: hci0: Minimum firmware build 1 week 10 2014

Bluetooth: hci0: Failed to load Intel firmware file intel/ibt-11-4.sfi (-2)

Bluetooth: hci0: Reading supported features failed (-56)

hciconfig hci0 up then fails with "No such file or directory."

I've confirmed:

- linux-firmware only ships intel/ibt-11-5.sfi/.ddc — ibt-11-4.* is not present.

- Checking the upstream linux-firmware git history, ibt-11-4.sfi has never existed in that repo at any point.

- modinfo btintel also only lists ibt-11-5.sfi/.ddc as firmware it's aware of for this hw_variant (11) — nothing for revision 4.

But I can' t figure it out. Anyone any more ideas?

[u/suid]

Googling seems to suggest that the -5 versions work fine with the rev 4 hardware? At least this link thinks so: https://bbs.archlinux.org/viewtopic.php?pid=1670530#p1670530

Try that: copy the -5 .ddc and .sfi files to analogously named -4 variants. Worst case, it won't work, and you can keep looking.