I use Simplicity Commander from the command line to work with my EFR32 devices. Recently, I've been getting some errors like "ERROR: A target device must be specified using the device option." What's going on?
Simplicity Commander's (initially optional) --device argument is now required in order to support parts and boards that cannot be automatically determined. The --device argument is described in UG162: Simplicity Commander Reference Guide.
Pro Tip: using the entire part number (eg., "--device EFR32MG1B232F256GM48") for every command can be ungainly. You can use "--device Cortex-M4" for all EFR32-based parts and Commander can then query the device to determine the actual part description.