When using the on-board J-Link interface on the Energy Micro EFM32GG-DK3750 and EFM32LF-DK3650 boards the debugger locks up with a Communication timed out: Requested 4 bytes, received 0 bytes ! error message.
Replace the existing $(StudioDir)/bin/JLink.dll (Windows) or $(StudioDir)/bin/JLink.so (Linux) file with the version in the attached .zip file.
CrossWorks for ARM release V2.1.1.
Planned for CrossWorks for ARM release V2.1.2.