ZIP file support for nRF Connect FOTA

[mchartier]

While testing FOTA upgrades it seems ZIP files are not supported by the iOS Device Manager app. Here is the error when I select dfu_application.zip in the Device Manager app:

Is this only a limitation with the Device Manager app? Or is this also a limitation with the firmware? Maybe I am missing some build configuration to enable this feature?

Also related to this, I noticed the size of the ZIP file is the same as the BIN file. It appears the ZIP file is created with compression disabled. Is this intentional or a bug? 

My environment:

nRF Connect 2.1.0
MacOS 13.0 on M1
Device Manager 1.2.8 (4)
SDK project: zephyr/samples/subsys/mgmt/mcumgr/smp_svr

[Hieu]

Hi mchartier,

Do you consistently encounter this error?

The iOS app is supposed to support zip file. However, I could not get hold of an iOS device today to try to reproduce your issue. I will get to that on Monday.

How did you produce the zip file? If it is from the <build folder/zephyr folder, then it is a DFU package meant for nRF Cloud. It is just a storage archive to bundle the binary and a manifest file together, so no compression is intentional.
It should actually be a slight bit (~1KB) heavier than the bin file, which is why I am not immediately sure you got the zip file from the zephyr folder.

That zip file probably still works with the iOS app though. I need to double check with a real phone on Monday.

[mchartier]

Hi, the zip file comes from the folder: smp_svr/build/zephyr

The zip file is created by the build system for this sample project. I made no changes to the sample project. 

I tested again today and get a different error from the Device Manager app when I tap on "select file" and then pick the file dfu_application.zip. The error is "Error Loading File: Unable to Decode Manifest JSON File." See screenshot.

I have attached the zip file.

8270.dfu_application.zip

[Hieu]

The new error message is updated by the engineer behind the app when I talked to him about your original ticket. I believed that the app updated sometime during the weekend?

I tested with an iOS device and an Android device today and talked further with the same engineer. We confirmed that there was some mismatch in expectation of the iOS app and the NCS manifest.json generation, which resulted in the iOS app to complain about the file.

There should be an app update for it soon and I will let you know here when it is available. In the meantime, I hope that using the .bin file is alright as an alternative?

[mchartier]

Yes I can use the bin file for now, thanks for the update.

Could you confirm that compressed bin files are not supported? I was hoping to use compressed files to reduce the time it takes to transfer the files over bluetooth.

[Hieu]

The compressed file will need to contain both the .bin and the manifest.json, just like the auto-generated one. The nRF Connect Device Manager at least need the data from the manifest file to work.

The key issue is that your Bluetooth transfer time will not improve, because the file will be decompressed at the phone, not at the device. If you want to transfer compressed data, you will need to implement your own decompression feature into the bootloader/application. I am not sure that is trivial, or possible at all given the usual RAM and flash size. Decompression can take a lot of RAM.