Modifying Boot Loader

[tamo2]

Hi,
We have been porting our existing software running on an embedded Linux system to Inforce6601/Linux. One of the features we need is a system recovery -- which recovers failed system (possibly by miss-configuration, or corrupted filesystem, etc.).
The assumption is that the boot loader is still intact and working,

The recovery mode is kind like the fastboot mode, except that we would like to kick in to the mode by sending a special Ethernet packet to the boot loader. Out system will be embedded in a larger system so reaching to our board is very difficult, and Ethernet is the only communication method from the host.

The boot loader will need to poll the special packet for a certain period of time before loading the kernel.

So here are the questions:
Q1. Is the source code available for the boot loader (I assume it is called APPSBL)?
Q2. Is the boot loader specific to InForc6601, or is it common to Snapdragon820?

Thanks,
tamo

[ashwin]

Hi Tamo

The bootloader source is closed at present. You can access it in src/bootable/bootloader/LK. However compiling it and flashing the emmc_appsboot.mbn would result in a bricked board as the appsboot does not have the required signatures.

The appsboot supplied is currently common for our 820 platforms.

Best Regards,
Ashwin

[tamo2]

Hi Ashwin,

Is the bootloader code going to be available in the future so that we can modify it and flash it to the board without bricking the system? Or is there a way around needing a required signature?

Thanks,
tamo

[ashwin]

Hi Tamo,

Unfortunately the bootloader/LK signatures will not be made available as they are proprietary to qualcomm. There are emmc_appsboot.mbn files available with the signatures in every release. You can flash this on your board(these images have the required signatures).

Best Regards,
Ashwin

[tamo2]

Ashwin,
I have additional questions.
The recent FASTBOOT supports Ethenet (https://chromium.googlesource.com/aosp/ ... /README.md).

Q3. Does InForce FASTBOOT support Ethernet?

Q4. Is there any way to get into FASTBOOT mode other than pushing VOL- and PWR buttons? Such as, sending special packets to Ethernet?

Thanks,
tamo

[ashwin]

Hi Tamo,

Unfortunately this feature is not enabled on the existing release for IFC6640/IFC6601.

Best regards,
Ashwin