WEC7 December 2019 update woes...
UPDATE:: On 26 March 2020, Microsoft uploaded a fixed version of the WEC7 December 2019 update to their DPC site. Direct link (you'll only be able to access this if you have an account with "Indirect Embedded / IoT OEM" permissions).
Somebody at the Microsoft update team uploaded the WEC7 December 2019 update in the wrong format. If you try to update using WEDU it will fail, and if you download the file from the Device Partner Center site you will see it is in the .zip file format (instead of the normal .img ISO format). Note that you need to register and request "Indirect Embedded / IoT OEM" permissions to see all Embedded updates on the DPC site.
If you unpack the X22-25842.zip file you get these files:
That doesn't look like a normal update at all but in fact it is, just a little bit in disguise... It's in DDP (Disc Descriptor Protocol) format, a format used to describe a replication master. Looks like Microsoft just simply forgot to convert this into a normal .img ISO file.
The .img ISO file can be recreated by simply concatenating the two IMAGE.DAT files from the Layer0 and Layer1 folder. On a command prompt, type the following command:
copy /b Layer0\IMAGE.DAT+Layer1\IMAGE.DAT X22-25842.img
You can now mount the .img file as you normally do (we use the excellent Elorabytes Virtual CloneDrive freeware to easily mount .img files).
Now you can install the WEC7 December 2019 update. It should complete without any errors. If the concatenation didn't go well (or if you just mount the IMAGE.DAT file from the Layer0 folder) you will get errors like this:
Note that the WEC2013 December 2019 update is in the right (.img) format and can be installed as normal.
The issues have been reported to Microsoft, so hopefully it gets fixed soon.