DebugLogger is a software driver that lets you log kernel-mode debug output into a file on Windows. This version is for Windows Phone 8.1
Logs are written in the file C:\Data\USERS\Public\Documents\wp81DebugLogger.log of the Windows Phone.
Beware: you have to stop the driver to be able to copy the file from the device. See command WP81SERVICECTRL.EXE of wp81Elevation to stop the driver.
See https://github.com/tandasat/DebugLogger
Compilation requires Visual Studio 2015 with Windows Phone 8.1 support.
Execution requires a Windows Phone 8.1 rooted with WPinternals.