These instructions will help you flashing the prebuilt bootloader
and AOSP images(built from sources) on db845c.

First, you wil need to have first built AOSP for the
db845c-userdebug lunch target.


Boot the board into fastboot mode:
----------------------------------
The easiest way to boot into fastboot mode is to run something
like "adb reboot bootloader" from the host, or
"reboot bootloader" on the device.  However, this
functionality may depend on the software installed on the board
to work, so you may need to manually enter fastboot mode as
follows.


To manually enter fastboot mode:
--------------------------------
* To manually boot the board into fastboot mode, press DOWN arrow
  key over serial UART console when restarting the board.

                         OR

* Disconnect the power *and* USB-C cable. Flip the board over, and
  while holding down the "VOL-" button plug in the power cable.
  Continue holding down the "VOL-" button and tap the "ON/OFF"
  button. The board should then boot to fastboot mode. Be sure to
  then re-connect the USB-C cable so that you can flash the board.

If HDMI is plugged in, you should see a text based
"FastBoot Mode" prompt on your screen. Or you can check by running
"fastboot devices" on your host which will print something like:

  $ fastboot devices
  c4e1189c        fastboot


Flash the board:
----------------
Once the board is in fastboot mode, you can then flash it by
running the following from the
device/linaro/dragonboard/installer/db845c/ directory:

  $ ./flash-all-aosp.sh <optional_kernel_binary>


This will flash the bootloader binaries, AOSP images (userdata.img
and super.img), and will also generate and flash boot.img if kernel
binary (in Image.gz-dtb format) is passed to the script.


Troubleshooting:
----------------
* Make sure the USB-C cable is connected. As it has to be
  removed to fully power the device down, it is easy to forget
  to reconnect it!

* If you cannot get the board into fastboot mode, or for some
  reason the flash-all-aosp.sh script does not work, you can do
  a full recovery flash of the board using the following
  instructions.


Recovery:
--------
First boot into recovery mode. After removing the power cable
and the USB-C cable, connect power while holding the "USB"
button (next to volume buttons near the USB-A ports). While
continuing to hold down the "USB" button, tap the "ON/OFF"
button. Then re-connect USB-C cable. There will be no HDMI
display output in recovery mode, and initially no serial output.

Then run the recovery script from the
device/linaro/dragonboard/installer/db845c/ directory:

  $ ./recovery.sh

This will do a recovery flash of the ptable and bootloader
binaries. After it is finished, the board will reboot.

Depending on the state of the board, it will enter fastboot
or may boot to a previously installed kernel. At that point
you may start again from the top of this document.