Containers used for secure device firmware ugprade that cannot be executed directly on target but must be processed by the bootROM first.
Secure binary is a binary output file that contains the user's application image along with a series of bootloader commands. The output file is known as a "Secure Binary" or SB file for short. These files typically have an .sb extension.
This format has a long history, the latest version is 3.1. (2022). SPSDK nxpimage tool supports SB 2.1 (2.0) and SB 3.1.
sb2 sb3