Yeah, I see the "HCI_ERROR_AUTH_FAIL" in your output, so that would indicate it has something to do with the security.

Maybe simply selecting a different security type would work in your case. Maybe it's not a BT3/BT4 problem, but merely finding a way to get the WT32i and your headunit to agree on a security protocol.

By the way, you wanted to know what the "760408" string was in your output. I think that's the bluetooth Class Of Device bitmask for your headunit, in hexadecimal, based on the docs (section 7.12 of the iWrap 6 command reference).

Look up the references for pairing and security in the iWrap 6 command reference. Look at section 6.38 ("PAIR"), 6.66 ("SET BT SSP"), and 6.51 ("SET BT AUTH").

In particular, I suggest trying SET BT AUTH with a specific PIN code. It says that the PIN can be 0-16 characters, so I think that your suspicions about the 8-digit PIN are unfounded.

If it helps, below is the onscreen output from a successful pairing process with my bluetooth headset. Yours is the same except that your gets an authentication error instead of OK. I suspect you merely need to poke at the commands I referenced above to find the exact combination of magic words to get it to pair.


--> INQUIRY 30
INQUIRY_PARTIAL 0c:e0:e4:6c:75:68 240404
------------------------------------
Pairing with device address:
0c:e0:e4:6c:75:68
------------------------------------
--> PAIR 0c:e0:e4:6c:75:68
INQUIRY 1
INQUIRY 0c:e0:e4:6c:75:68 240404
PAIR 0c:e0:e4:6c:75:68 OK
--> CALL 0c:e0:e4:6c:75:68 19 A2DP
CALL 0
CONNECT 0 A2DP 19
--> CALL 0c:e0:e4:6c:75:68 17 AVRCP
CALL 1
CONNECT 1 AVRCP 17
CONNECT 2 A2DP 19
--> A2DP STREAMING START
AVRCP 1 GET_CAPABILITIES 2
--> AVRCP RSP
A2DP STREAMING START 0
--> A2DP STREAMING START
Empeg state...................................PLAYING >
AUDIO ROUTE 0 A2DP LEFT RIGHT
Detected: Pairing Mode is Complete.
--> SET CONTROL RECONNECT 600 0 0 7 0 A2DP A2DP AVRCP
STORECONFIG
--> A2DP STREAMING START
Empeg state...................................PLAYING >
--> A2DP STREAMING START
Empeg state..................................PAUSED ||
--> A2DP STREAMING START
Empeg state...................................PLAYING >

--------------------------------------
Pairing process ended.
--------------------------------------