Download the Android kernel in an emulated environment on the device

Question

I am trying to compile a new Android kernel on my phone. The problem is that it ends in the load cycle without any means of accessing error messages. I can compile an older version of the kernel that works well on the phone, so I can add the box to the configuration if necessary.

My goal is to load the phone with the old working operating system, and then load the new kernel from the working OS and receive log messages while loading the new kernel.

If this is not possible, there is a way (for example, saving messages to an SD card) for accessing kernel log messages (errors) later (after loading another working OS).

Answer 1

I do not know if this will help you, but I found a way to load the Android kernel with console messages on the screen. You need to boot your device in fastboot mode - it can be very difficult for different devices, here are some general information about fastboot: http://android-dls.com/wiki/index.php?title=Fastboot For my device I can get access to the bootloader using adb and the command:

adb reboot bootloader 

You will need to have the fastboot binary on your computer. Then connect the phone to the computer in fastboot mode and write the following command:

 fastboot boot [path/to/your/kernel] 

The phone should try to load the kernel and print some messages on the screen. You may need to configure some parameters, such as command line arguments passed to the kernel (look at the output from the fastboot help).