In-Field Update & hex files

Is there any way to automatically create the hex file during the build process or update the device without the hex file?

I can’t see any hex file created during the build process in Visual Studio. Despite that the Visual Studio is able to program the device. I currently have multiple projects with reference to one lib project. Every time the code changes I need to manually obtain the hex file (deploy the code to device and download back the hex file from device) for each project.

I don’t understand why this cannot be possible. How Visual Studio programs Fez device without the hex file?

VS uploads the le/be dll files. The actual linking of them is done on the device.
This can then be read back as a hex file.
I actually don’t know why it is done that way.
The advantage is that every change is tested on hardware at least a little bit, before the hex files gets deployed to many devices.

Can I upload the dll files to the device using mfdeploy or other tool?

No I don’t think so.
I guess the Deploy API provides all you need for this, since VS can do it. But this is not available from MFDeploy.
But you can put the dll’s onto a SDCard, and load them dynamically at runtime.
This is called reflection. Just follow the link that was posted by andre.m above.

correct, my mistake