RE: DFU-OTA SDK11 to SDK15

Einar Thorsrud — Fri, 26 Oct 2018 11:41:12 GMT

Hi,

We need to know more about the errors you are getting in order to suggest a solution, but it should be possible to do this upgrade. As you are changing the major version of the SoftDevice, you have to update the bootloader and SoftDevice together in a single DFU image. That should not be a problem, provided you take the following into account (which it seems you might have done):

If you have already adjusted for the increased bootloader size, then that should be OK, but typically i assume units in the field does not have this adjustment? If not, then you can rewrite the UICR to contain a new bootloader start address using a special legacy bootloader (which would then be an intermediate step). This post describes it in detail.
If you update to a bootloader from a SDK version < 15.0.0 and use a SoftDevice with a different size, you will get a failure due to the bootloader not handling a change in SoftDevice size (and thus application start address). That is not a problem with SDK 15, though, so it should not affect you.