> ## Documentation Index
> Fetch the complete documentation index at: https://dragonwingdocs.qualcomm.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Troubleshoot using sample logs

The universal asynchronous receiver/transmitter (UART) logs enable you to monitor and debug the data exchanged between the Qualcomm Linux software and a device using a UART interface.

The sample UART logs help you identify the various stages of system bootup. In the event of a crash, you can use these logs to do the following:

* Determine the stage at which the crash occurred
* Gain a high-level understanding of the execution process

[PBL/XBL log](./troubleshoot-using-pbl-xbl-log)

The sample primary boot loader/eXtensible boot loader (PBL/XBL) log indicates the start and end of the PBL and XBL.

[UEFI log](./troubleshoot-using-uefi-log)

The UEFI log provides information about the start and end of UEFI.

[U-Boot log](./troubleshoot-using-uboot-log)

The U-Boot log provides information about the start and end of U-Boot.

[Linux log](./troubleshoot-using-linux-logs)

The sample log signifies the start of the Linux boot process.

[Capsule update logs](./troubleshoot-using-capsule-update-logs)

The capsule update log provides information about the start and end of the capsule update.