"Computing hop increment" never ending

I have a problem that the “Computing hop increment” is never ending.

So the -i works fine:

$ btlejack -i
BtleJack version 1.1

[i] Flashing /Volumes/MICROBIT ...
[i] Flashed 1 devices

The -s as well:

$ btlejack -s
BtleJack version 1.1

[i] Enumerating existing connections ...
[...]
[ - 87 dBm] 0xaf9a8da1 | pkts: 50
[...]

But then I do -f and even after 20 minutes the “Computing hop increment” is not finishing:

$ btlejack -f 0xaf9a8da1
BtleJack version 1.1

[i] Detected sniffers:
 > Sniffer #0: fw version 1.1

[i] Synchronizing with connection 0xaf9a8da1 ...
✓ CRCInit = 0xbbc761
✓ Channel Map = 0x1f80680043
✓ Hop interval = 2
\ Computing hop increment^C[i] Quitting

When I aborted and tried again I actually got different Channel Map values (it was still the same BLE connection). Is that a problem (I’m not very familiar with the bluetooth protocol) or expected? Here’s the output of the second run:

btlejack -f 0xaf9a8da1 -j
BtleJack version 1.1

[i] Using cached parameters (created on 2018-08-21 14:07:57)
[i] Detected sniffers:
 > Sniffer #0: fw version 1.1

[i] Synchronizing with connection 0xaf9a8da1 ...
✓ CRCInit: 0xbbc761
✓ Channel Map = 0x1fc3200000
✓ Hop interval = 2
/ Computing hop increment

It’s an iphone 6 talking to a Bluetooth headset (no PIN pairing, I guess it’s the “just works” protocol). I’m using btlejack on MacOS.

[FrancescoTaurino]

Thank you for your feedback!

[floyd-fuh]

My Coworker worked with 2 microbits, which was a little bit better but still not good. I personally have only worked with 1. So to answer your question: For certain bluetooth devices the “Computing hop increment” never terminated, for others it did with only 1 microbit.