DFU doesn't work with iOS13 on iPhone8 / iPhoneX

[Fabian Hauschild]

Hello everyone,

We are having a problem with the DFU function in our custom iOS app.

We are using DFU library version 4.5.1.

After updating SoftDevice and Bootloader the DFU library returns an error befor updating the application. (Update worked with iOS 12)

This Error occures with iPhone8.

With iPhoneX DFU library returns an error before updating SoftDevice and Bootloader (before connecting to the Device).

The Update workes fine with iPhone7 and iPhone11.

The update works fine with the DFU function in the nrf Tollbox App with all iPhones.

How could this problem be fixed?

Are there known issuse with theese iPhones / iOS Version and the DFU library?

Best Regards 

Fabian

[Einar Thorsrud]

Hi,

You do not specify what error you get, but I notice that you write it works with the Toolbox App on all tested models, so it is only with your app it fails. I assume you are using  IOS-Pods-DFU-Library? I suggest you first try to set a low number for packet receipt notification (PRN), for instance, 1. If that does not help, can you describe the error more? At which point does the error occur, and what error is reported both on the iOS side and the nRF side?

[Fabian Hauschild]

Hi,

Yes we are using the IOS-Pods-DFU-Library.

Setting a low PRN didn't help. The App Developer told me that PRN is set to 0 by the DFU Library.

The error seems to be a timeout during the connect phases before SoftDevice update and before application update.

I've updated the project to SDK Version 16.0.0 and SoftDevice S140V7.0.1.

The new Bootloader is the example provided by SDK 16.0.0 (examples\dfu\secure_bootloader\pca10056_s140_ble) . I've only changed the key file.

With the new bootloader I get this error message when updateing the Application with nrf Tollbox (iPhone 8). 

With an iPhone 7 everything works fine.

[Einar Thorsrud]

Hi,

I suspect this is due to the PRN. Setting PRN to 0 disables it. What you should do is reduce it (from 12 which is the default) to 1. You do that by adjusting the packetReceiptNotificationParameter property of the DFUServiceInitiator object. Please let me know if that does not fix the issue.

[Fabian Hauschild]

Hi,

in my bootloader I've changed the PHY_UPDATE_REQUEST from BLE_GAP_PHY_AUTO to BLE_GAP_PHY_1MBPS. 

This seems to fix all the problems with the Update.

After this fix the update works with iPhone8 and iPhoneX with your toolbox app and our custom app.

I think the 2MBPS PHY was causing this problems.

case BLE_GAP_EVT_PHY_UPDATE_REQUEST:
        {
            NRF_LOG_DEBUG("Received BLE_GAP_EVT_PHY_UPDATE_REQUEST.");

            ble_gap_phys_t const phys =
            {
                .rx_phys = BLE_GAP_PHY_1MBPS ,
                .tx_phys = BLE_GAP_PHY_1MBPS ,
            };

            err_code = sd_ble_gap_phy_update(p_gap->conn_handle, &phys);
            APP_ERROR_CHECK(err_code);
        } break;

Note:

We didn't change the PRN 

[Einar Thorsrud]

Hi,

I am glad to hear you got it working. This change effectively does the same thing as setting a low (but not 0) PRN. The point of setting a low PRN in this case, which you also achieve with forcing 1 Mbps PHY (instead of automatically switching to 2 Mbps), is that you reduce the rate of incoming data, which is not properly handled by the bootloader if it is too high.