# Program images Source: [https://docs.qualcomm.com/doc/80-Y8730-2/topic/program_images.html](https://docs.qualcomm.com/doc/80-Y8730-2/topic/program_images.html) Program images include PBL, SBL, and APP images. See the following sections for details about the function, format, and runtime memory status of each program image. ## PBL image Source: [https://docs.qualcomm.com/doc/80-Y8730-2/topic/program_images.html](https://docs.qualcomm.com/doc/80-Y8730-2/topic/program_images.html) The PBL image is in the PBL region of the RRAM, as shown in [QCC730 memory and image structure](https://docs.qualcomm.com/doc/80-Y8730-2/topic/qcc730_application_development.html#qcc730_memory_layout_0). Qualcomm owns the PBL image and programs it to the PBL region. Customers can't modify it. ### Function The PBL image performs the following tasks: - Handle different boot cases - Choose SBL image from FDT after OTA update - Authenticate SBL image - Load SBL image ### Image structure Although the PBL image is locked and can't be modified after the chip leaves the factory, a patch for the PBL image is allowed. The patch file is built into the SBL image as an independent segment. ## SBL image Source: [https://docs.qualcomm.com/doc/80-Y8730-2/topic/program_images.html](https://docs.qualcomm.com/doc/80-Y8730-2/topic/program_images.html) The SBL image is stored in the SBL region of the RRAM. To support OTA update for SBL images, QCC730 has two SBL memory regions. For more information, see [QCC730 memory and image structure](https://docs.qualcomm.com/doc/80-Y8730-2/topic/qcc730_application_development.html#qcc730_memory_layout_0). ### Function The SBL image performs the following tasks: - Choose APP images according to the partition table in flash - Authenticate APP images - Hash-verify APP images - Load APP images ### Image structure QCC730 only supports SBL images that are in executable and linking format (ELF). Based on the content, an SBL image mainly includes several segments as shown in the following figure. Figure : SBL image structure PBL patch segment PBL patch segment ELF/PHR ELF/PHR Data segment Data segment Hash segment Hash segment Code segment Code segment - **Hash segment**: This segment includes information for the image signature and hash value of each segment. - **Code/data segment**: These segments include sections of SBL TXT, data, and basic service set (BSS) section. - **PBL patch segment**: This segment includes the patch for PBL. ### Memory layout for SBL SBL runs in the RAM, which has a 64 KB space (0x80000 to 0x90000) reserved for SBL. Figure : SBL memory layout SBLB SBLB PBL patch PBL patch FDT FDT PBL PBL 0x20A400 0x20A400 0x212400 0x212400 0x21A400 0x21A400 32K 32K SBLA SBLA 32K 32K ELF ELF Hash segment Hash segment Code segment Code segment Data segment Data segment PBL patch segment PBL patch segment Config table Config table PBL RAM PBL RAM RAM RAM SBL RAM SBL RAM 0x8000 0x8000 0x80000 0x80000 0x90000 0x90000 0xA0000 0xA0000 ## APP image Source: [https://docs.qualcomm.com/doc/80-Y8730-2/topic/program_images.html](https://docs.qualcomm.com/doc/80-Y8730-2/topic/program_images.html) An APP image contains the final programs that run on QCC730. Due to the limited size of the RRAM, APP images are stored on the external flash. To support OTA update, two APP regions are required on the flash. ### Function An APP mainly includes functions such as WLAN, peripheral, and system. ### Image structure Figure : APP image structure RRAM code segment RRAM code segment ELF/PHR ELF/PHR RAM data segment RAM data segment Hash segment Hash segment REGDB/CALDB segments REGDB/CALDB segments RAM code segment RAM code segment An APP ELF image includes the following segments according to the content: - **Hash segment**: This segment includes the information for the image signature and hash value of each segment. - **RRAM code segments**: These segments include sections of APP TXT running on RRAM. - **RAM code/data segments**: These segments include sections of APP data, BSS, and TXT running on RAM. Running these sections on RAM is based on performance considerations. - **REGDB/CALDB segment**: This segment includes the WLAN REGDB and CALDB. ### Memory layout for APP image When an APP image runs, each segment of the image is loaded to the corresponding memory address according to its virtual address. The code and data segments executed in RAM is loaded from flash to RAM, and the code executed in RRAM and REGDB/CALDB are loaded to RRAM. The following diagram illustrates the layout of each memory in detail. Figure : Memory layout for APP RRAM RRAM Flash memory Flash memory APP_B APP_B APP_A APP_A APP APP RAM RAM RRAM code segment RRAM code segment REGDB/CALDB segment REGDB/CALDB segment ELF ELF Hash segment Hash segment REGDB/CALDB segment REGDB/CALDB segment RAM data segment RAM data segment RAM code segment RAM code segment RRAM code segment RRAM code segment RAM data segment RAM data segment RAM code segment RAM code segment Last Published: Jun 03, 2026 [Previous Topic QCC730 images and binaries](https://docs.qualcomm.com/bundle/publicresource/80-Y8730-2/topics/qcc730_images.md) [Next Topic Configuration BIN binaries](https://docs.qualcomm.com/bundle/publicresource/80-Y8730-2/topics/configuration_bin_images.md)