The EHCI Debug Port is an optional capability of EHCI controllers which can be used for early debugging for hardware which does not have a serial port. All USB2 host controllers are EHCI controllers.
Since I installed Coreboot on my Librem, I experienced some issues. In order to investigate - and since the Librem has no serial port - I aimed to do some Coreboot and kernel debugging with a Raspberry Pi Zero.
DISCLAIMER: try anything described here at your own risk! These are just my notes. That it did work for me then does not mean this would work for you now.
After successfully installing coreboot on my librem 13 v1, I noticed that unfortunately the wifi wasn’t working anymore. Since the coreboot version I flashed previously wasn’t quite new, I decided to build a new rom image myself using the newest coreboot source code.
DISCLAIMER: try this at your own risk! The information below it’s just a summary of my notes and experiences during the installation of coreboot on my notebook.
I am the proud owner of a Librem 13 v1 (bought in September 2016). Currently all librem laptops are shipped with coreboot installed on them, but mine was still shipped with propietary firmware on it. Fortunately coreboot is supported anyway - it was possible for me to install coreboot myself.
The Asus Chromebook Flip C101PA (bob) is a convertible touchscreen laptop powered by an ARMv8 Rockchip RK3399 hexa-core processor and 4GB RAM, measuring 10.4" x 7.2" x 0.6" and weighing 1 kg.
Features:
Rockchip RK3399 (OP1) dual-core 2.0GHz Cortex-A72 and quad-core 1.4GHz Cortex-A53 processor 4GB LPDDR3 RAM 10.1" 1280x800 LED display Mali T860MP4 GPU 16GB eMMC 38 Whrs battery 2x USB 3.1 Type-C ports 1x USB 2.0 Type-A port ARM Chromebooks ship with the Coreboot bootloader and use Depthcharge as the payload.
Radxa Rock 2 Square is a Rockchip RK3288 based solution.
Available images
The available images run with:
A modified version of u-boot The Rabian operating system (which is based on Debian 8) A custom radxa kernel. The goal is to get a pure Debian distribution up and running on the board:
Debian u-boot Debian armhf linux-image kernel Pure Debian root file system For this small project, we have two Radxa Rock 2 Square boards:
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