Some early revisions of single-band radio daughter cards include an on-board SPI flash module that is improperly connected to the system. This can lead to the SPI flash remaining active and consuming current (~3mA) far in excess of what is expected from the daughter card (for example, when monitoring current consumption with Energy Profiler while the MCU is in a low-energy state).
Affected boards do not implement a pull-up resistor on the FLASH_SCS line from the SPI flash device. This can lead to the node floating low, which will lead to the active SPI flash current consumption. Impacted board revisions:
Manually pulling the FLASH_SCS node high will shut down the SPI flash device, eliminating the excess current consumption. This can be accomplished by physically adding a pull-up to this node on the radio board. Alternatively, you can drive the associated pin HIGH (example: on BRD4153A, MCU pin PA4 is tied to the FLASH_SCS net) from the EFR32xG device.
This issue has been fixed on all affected boards. The "Revisions prior to..." text in the list above indicates the board revision in which the fix first appears for each respective board.