# Boot documentation This guide explains the supported boot features, the architecture of a cold boot (which starts from a power-off state), and the interfaces for the Qualcomm^®^ Linux^®^ system software. Additionally, this guide provides instructions on how to develop a unified extensible firmware interface (UEFI) application, configure the Devicetree (DT) interfaces, debug logs, and verify system bootup. For more information about UEFI, see [UEFI](https://docs.qualcomm.com/doc/80-80022-4/topic/uefi-develop.html#unified-extensible-firmware-interface-uefi). ## Boot overview Boot architecture Understand the key components within the boot architecture. https://docs.qualcomm.com/doc/80-80022-4/topic/boot-architecture.html#architecture1 APSS cold boot flow Configure the cold boot flow to initialize system components and load the operating system. https://docs.qualcomm.com/doc/80-80022-4/topic/bootloader-architecture.html#bootloader-architecture ## Tools to update boot configuration Configure the Devicetree binary (DTB) files Download, launch, and use DTB to configure DTB files and modify interfaces. https://docs.qualcomm.com/doc/80-80022-4/topic/configure-qdte.html#configure-qdte Generate the capsule Generate the capsule using the UEFI variable. https://docs.qualcomm.com/doc/80-80022-4/topic/capsule-update-and-recovery.html#capsule-update-and-recovery Flash the software using Fastboot Flash the Qualcomm software using Fastboot on to the connected devices. https://docs.qualcomm.com/doc/80-80022-4/topic/fastboot.html#fastboot ## Update the device firmware Set up the capsule Update the device firmware using a capsule through UEFI. https://docs.qualcomm.com/doc/80-80022-4/topic/capsule-update-and-recovery.html#capsule-update-and-recovery Update capsule and trial rollback in base and advance variants Understand the device firmware update via capsule for the base and advance variants, and rollback options. https://docs.qualcomm.com/doc/80-80022-4/topic/capsule-update-for-base-and-advance-variants.html#capsule-update-for-base-and-custom-variants ## Boot interfaces overview Platform information Devicetree (DT) Understand DT details for CDT, including platform version, type, major/minor hardware versions, subtype, and OEM-id. https://docs.qualcomm.com/doc/80-80022-4/topic/platform.html#platform-info Boot devicetree Configure boot functionality, including enabling/disabling user-initiated EDL, setting EDL timeout, and specifying USB cable options for EDL mode. https://docs.qualcomm.com/doc/80-80022-4/topic/boot-developer-touchpoints.html#boot-developer-touchpoints Power management integrated circuit (PMIC) Manage power supply requirements within a device using the PMIC. https://docs.qualcomm.com/doc/80-80022-4/topic/pmic-developer-touchpoints.html#pmic-developer-touchpoints General-purpose input/output (GPIO) functions - TLMM Configure GPIOs during boot using DT properties for TLMM, which controls GPIO and alternate function multiplexing. https://docs.qualcomm.com/doc/80-80022-4/topic/tlmm-developer-touchpoints.html#tlmm-developer-touchpoints Buses Configure QUP v3 serial interface device nodes using DT properties to facilitate data transfer among system components. https://docs.qualcomm.com/doc/80-80022-4/topic/buses.html#buses USB devicetree properties Adjust USB signal quality using DT properties. https://docs.qualcomm.com/doc/80-80022-4/topic/usb-developer-touchpoints.html#usb-developer-touchpoints ## Troubleshoot using sample logs Troubleshoot using PBL/XBL logs Troubleshoot boot issues using the PBL/XBL logs. https://docs.qualcomm.com/doc/80-80022-4/topic/bootloader-logs.html#bootloader-logs Troubleshoot using UEFI logs Troubleshoot boot issues using UEFI logs. https://docs.qualcomm.com/doc/80-80022-4/topic/uefi-log.html#uefi-log Troubleshoot using Linux logs Troubleshoot the boot process using Linux sample logs. https://docs.qualcomm.com/doc/80-80022-4/topic/hlos-logging.html#hlos-logging Troubleshoot using capsule update logs Troubleshoot the boot process using capsule update logs. https://docs.qualcomm.com/doc/80-80022-4/topic/capsule-update-logs.html#capsule-update-logs ## How to Trigger the capsule update Procedure to trigger the capsule update. https://docs.qualcomm.com/doc/80-80022-4/topic/How-tos.html#trigger-the-capsule Authenticate and sign the capsule Procedure to authenticate capsule-based system firmware updates. https://docs.qualcomm.com/doc/80-80022-4/topic/How-tos.html#authenticate-and-sign Update the device firmware using a capsule Procedure to update the device firmware using a capsule. https://docs.qualcomm.com/doc/80-80022-4/topic/How-tos.html#update-device-firmware Configure QDTE Procedure to configure QDTE and modify the DTB files. https://docs.qualcomm.com/doc/80-80022-4/topic/configure-qdte.html#configure-qdte Last Published: May 11, 2026 [Next Topic Boot overview](https://docs.qualcomm.com/bundle/publicresource/80-80022-4/topics/overview.md)