The gecko bootloader is not included in the sample code for SDK 2.7.0 or later, so you need to download the bootloader separately.

There is a difference in the bootloader included in the sample project between SDK 2.6.x and earlier and 2.7.0 and later, so it is necessary to understand the difference first.

The bootloaders included in the sample code for SDK 2.0.0 and later are as follows.

Bluetooth Smart SDK 2.0.0 ~ 2.6.x

• BGM1xx, EFR32BG1 → includes legacy OTA bootloader
• EFR32xG12, EFR32xG13 → project does not include bootloader

 
Bluetooth Smart SDK 2.7.0 ~

• BGM1xx, EFR32BG1, EFR32xG12, EFR32xG13 → project does not include bootloader

 
The sample code from SDK 2.7.0 onwards assumes the latest geckobootloader and will not work as expected on the legacy OTA bootloader. Therefore, if you are using SDK 2.7.0 or later, you need to download the bootloader first.


There are several ways to download the gecko bootloader.

• Create a GeckoBootloader project and build it to generate a Gecko bootloader binary. Then download the binary to your device. (First method)
• Create a GeckoBootloader project and build it to generate a Gecko bootloader binary. Then combine that binary with the user code binary and download it. (Second method, Third method)
• The demo app (not the sample code) that comes with SDK 2.7 or later includes the Gecko bootloader, so download it once.

Downloading the demo app is the easiest and recommended.

Detailed instructions are available on the Silicon Labs community site, so please refer here.