DFU fails intermittently with: Error 8: Operation not permitted

RE: DFU fails intermittently with: Error 8: Operation not permitted

Hung Bui — Mon, 15 Jul 2019 13:24:06 GMT

Hi Michael,

Having a look at the traces from iPhone XR and iPhone 7, I can see that the iPhone XR can send the firmware data much faster compare to iPhone 7. If you count the time from:
"DFU:Sending firmware to DFU Packet characteristic..."

until the next log, on iPhone XR it takes ~150ms when on iPhone 7 it takes 283ms.

This may suggest that it was due to the XR sending data too fast that causing the bootloader couldn't handle it. We need to check the connection interval of the connections.

If you can capture some sniffer traces to compare it would be great.

I would suggest to try increase the preferred connection interval to slow down the update speed from the iPhone XR.

RE: DFU fails intermittently with: Error 8: Operation not permitted

Hung Bui — Fri, 12 Jul 2019 15:03:30 GMT

Hi Michael,

Sorry for the late response, I was on vacation this week.

Good to know that you have a temporary workaround.

I will have a look at the traces. In the mean time, if possible could you capture the trace when the first update is success and the second update is failed ? (with packetReceiptNotifications = 12)

RE: DFU fails intermittently with: Error 8: Operation not permitted

mchartier — Wed, 03 Jul 2019 16:18:55 GMT

This issue was also logged on GitHub here: https://github.com/NordicSemiconductor/IOS-Pods-DFU-Library/issues/319

@phillips77 suggested to set packetReceiptNotifications to a small number so tested on iPhoneXR with setting == 1 and now we get 6 straight upgrades passed which never happened before. This implies the bootloader cannot handle the speed of the XR or there is some kind of flow control issues in the protocol.

The default setting for packetReceiptNotifications is 12. With this default setting the 1st upgrade after a power cycle always works and the 2nd upgrade almost always fails. This implies something is not getting set (or reset) in the bootloader when we trigger the upgrade. The device gets into a state where a power cycle is required.

For now we can work around the problem by setting packetReceiptNotifications==1 so this issue is not urgent. But it seems we do not know the root cause.

RE: DFU fails intermittently with: Error 8: Operation not permitted

mchartier — Wed, 03 Jul 2019 16:13:11 GMT

Here is the log of iPhone XR doing successful DFU.

devzone.nordicsemi.com/.../dfu_5F00_success_5F00_xr.txt

RE: DFU fails intermittently with: Error 8: Operation not permitted

mchartier — Wed, 03 Jul 2019 14:27:23 GMT

Here is the log of iPhone 7 doing successful DFU. iPhone XR will come later today.

devzone.nordicsemi.com/.../dfu_5F00_normal_5F00_verbose.txt

RE: DFU fails intermittently with: Error 8: Operation not permitted

Hung Bui — Wed, 03 Jul 2019 13:02:00 GMT

Hi Michael,

The log you provided looks quite strange.

After the init packet was exchanged and executed (at 2019-07-02 11:41:25.624 ) , the DFU master starts to transmit the image , but after creating the object with 0x0602 at 2019-07-02 11:41:25.698. It didn't send any image but request a CRC check and then execute the object which is very strange as there is no data has been sent yet.

Could you try capture a trace of sending the same image but with iPhone 7, as well as with iPhone XR but on a successful session ?

RE: DFU fails intermittently with: Error 8: Operation not permitted

mchartier — Tue, 02 Jul 2019 19:27:17 GMT

Here is the DFU log output with full verbosity turned on.

devzone.nordicsemi.com/.../dfu_5F00_error.txt