LTE Module Series
SC20 Secure Boot User Guide
SC20_Secure_Boot_User_Guide Confidential / Released 7 / 15
2 MSM8909 Secure Boot Flowchart
Figure 1: MSM8909 Secure Boot Flowchart
1. Power on the system and take MSM8909 AP CPU out from RESET.
2. Cortex-A7 APPS PBL:
a. Loads, executes, and authenticates the SBL1 segment #1 from SC20 to L2 (as TCM).
b. Loads, executes, and authenticates SBL1 segment #2* (DDR/SDI equivalent) to RPM code RAM,
then jumps to SBL1.
3. SBL1#1
a. Loads and authenticates the QSEE/TZ image from the boot device to DDR.
b. Loads and authenticates the RPM firmware image from the boot device to RPM code RAM.
c. Loads and authenticates the HLOS APPSBL image from the boot device to DDR.