DFU failing for control point characteristic with Unlikely Error on iOS

[Darshan R]

Hi,

I am an iOS developer trying to implement the app for an nrf51822 chip-based device. I am trying to perform DFU of application type using the objective-C files from the nRF-Toolbox app. But every time the startDFU method in DFUOperationDetails tries to write to the control point characteristic, its failing with 'Unlikely error'. The difference I can see from the toolbox app is that I am connecting to the device using my own CBCentralManager on the main thread itself and passing it to DFUOperations.

I have attempted performing DFU directly from the nrfToolbox app, which works on few occasions, but also fails on few occasions. So kindly guide how I can resolve this issue and let me know if you need more details.

iOS version - 8.4

[Vidar Berg]

It should be stable with nrftoolbox, if it's not it could be an indication that there's is a problem with the bootlaoder FW itself.

I think a good place to start is to see if you could get it to work consistently with nrf toolbox first.

Some follow up questions:

• Are you using a Nordic development kit, or a custom board?
• If it is a custom board, does it have an external LF crystal?
• Does the chip variant have 16 or 32KB RAM?
• Which SDK version is the bootloader based on?
• Is the 'number of packets' set to '10' in ios settings -> nRF toolbox

[Darshan R]

Hi,

Find the answers below -

-Are you using a Nordic development kit, or a custom board? - Custom Board -If it is a custom board, does it have an external LF crystal? - No -Does the chip variant have 16 or 32KB RAM? – 16KB -Which SDK version is the bootloader based on? – 6.1.0