Bootloader Firmware Programming#

If Secure Boot is enabled, a SIGNED version of the bootloader firmware must be programmed to the flash.

Instructions on how to sign the bootloader firmware can be found in sections Signing for ECDSA-P256-SHA256 Secure Boot and Signing for Certificate-Based Secure Boot in Series 2 and Series 3 Secure Boot with RTSL.

The bootloader starting address is device dependent. For more information about the bootloader starting address, see Memory Space for Bootloading.

Flashing the bootloader firmware using Simplicity Commander is similar to flashing the SE Firmware upgrade application.

commander flash --masserase <bootloader file> --device <device name> --serialno <J-Link serial number>

where <bootloader file> is the name of the bootloader firmware file.

For TrustZone-aware bootloaders, the <bootloader file> is the combined image of Secure and Non-secure bootloaders. To check the Boot status of the device, run the security status command.

commander security status --device EFR32MG21A010F1024 --serialno 440048205

SE Firmware version : 1.2.14
Serial number	    : 000000000000000014b457fffe045a8e
Debug lock	        : Disabled
Device erase	    : Enabled
Secure debug unlock : Disabled
Tamper status	    : OK
Secure boot	        : Disabled
Boot status	    : 0x20 - OK
DONE

Any Boot status other than 0x20 – OK indicates that the secure boot process has failed. It means the bootloader firmware is either unsigned or incorrectly signed. The only way to recover is to flash a correctly-signed image (see section Recover Devices when Secure Boot Fails in Series 2 and Series 3 Secure Boot with RTSL).

For Series 3, make sure that code region 0 is closed.

commander security readregionconfig -d sixg301

Index        : 0
Size         : 32 kB
Protection   : Encrypted and authenticated
Closed       : False

Index        : 1
Size         : 1984 kB
Protection   : Encrypted and authenticated
Closed       : False

DONE

To close region 0, run the following command:

commander security closeregion 0 -d sixg301

Note: the default behavior of the commander flash command is to close regions once programming is complete.

Successfully closed code region 0 (version 0x00000000)
DONE