Thoughts dereferenced from the scratchpad noise.

Building Android 4.2 LiveSuit image for Cubietruck (Allwinner A20)

Published at September 16, 2015 · Piotr Król · 7 min read

Treating A20 boards like outdated piece of HW by vendors makes building Android for Cubietruck not trivial task. Finding documentation, mailing list or blog post that clearly describe steps is almost impossible. Most of links to SDK are broken and instructions outdated. Because of that I decided to leave couple notes for me and all of you lost in this madness. Hopefully below steps can build foundation for future development and improvements....

Categories: os-dev

Setup for Linux kernel development on Cubietruck

Published at September 1, 2015 · Piotr Król · 8 min read

During last couple of months I see quite big interest in building products on A20 SoC. This chip can be bought for 6USD in quantity. Most important features are: Dual-Core ARM Cortex-A7 (ARMv7) Mali-400 MP2 HDMI, VGA and LCD MMC and NAND OTG and 2 Host ports Tracking media related to low-end mobile market IMHO the hottest SoCs are Allwinner A20 and Rockchip RK3288. A20 ship with dozen development boards like Cubieboard or pcDuino series, Banana Pi, MarsBoard or Hummingbird....

Categories: os-dev

ESP-12 update to SDK v0.9.5 and AT v0.21.0.0? noobs tutorial

Published at January 25, 2015 · Piotr Król · 5 min read

January 23th Espressif published new ESP IOT SDK on their forum v0.9.5. My ESP-12 came with with pretty old version so I decide to update it to latest one: 1 2 3 4 5 6 7 8 9 10 AT+RST OK y_RSöfJ[úndor:www.ai-thinker.com Version:0.9.2.4] ready AT+GMR 0018000902-AI03 OK ESP-12 firmware update pin configuration As picture presents in addition to normal operation we have to pull down GPIO0 and pull up GPIO2....

Categories: firmware iot

Power on of ESP-12 (ESP8266)

Published at January 24, 2015 · Piotr Król · 3 min read

ESP8266 is a SoC made by Espressif. For last couple of months this chip is a rockstar of HackADay and makers community around the Internet. Mostly because of WiFi modules built based on it (ESP-XX family). Rich interface (GPIO, SPI, SDIO, I2C) give those boards potential to be standalone MCU with WiFi capability for wide range of applications. In quantity you can get ESP-01 for $2.7 (for 1kpcs). Of course there is no free lunch....

Categories: firmware iot

Raspberry Pi kernel repository aggregating patches for Linux mainline

Published at October 15, 2014 · Piotr Król · 3 min read

Since several months I’m trying to find my way to embedded Linux programming. My hardware set was very limited I had only one board that can be called “embedded” and it was Raspberry Pi. Because I am more interested in firmware/OS level then hardware I tried to figure out what is going on with RPi kernel. After taking brief review of raspberrypi/linux GitHub repository I realized that close to my heart is upstreaming effort....

Categories: os-dev

virtualbox-dkms: fix alloc_netdev problems when compiling with 3.17.0-rcX headers

Published at September 20, 2014 · Piotr Król · 4 min read

Intro Because of my bug hunting approach of using latest kernel I experienced problem with compiling VirtualBox modules with 3.17.0-rc5 version on my Debian Jessie. Issue is well known and described for examples here. Problem manifest itself with: 1 2 3 4 5 6 7 8 9 10 11 12 ------------------------------ Deleting module version: 4.3.14 completely from the DKMS tree. ------------------------------ Done. Loading new virtualbox-4.3.14 DKMS files... Building only for 3....

Categories: app-dev

How to fix backlight issue on IdeaPad y510p

Published at August 23, 2014 · Piotr Król · 1 min read

Today I decide to switch to latest kernel (3.17-rc1) on my IdeaPad y510p. I hit only one annoying problem until now - after booting my main screen was dimmed. I tried all instructions from top google hits for all possible configurations of keywords linux, y510p, backlight issue, etc. Especially I tried all methods from Arch Wiki. Finally I found solution, by greping modinfo for my Intel graphics card: 1 2 3 4 5 [23:55:24] pietrushnic:~ $ sudo modinfo i915|grep backlight parm: invert_brightness:Invert backlight brightness (-1 force normal, \ 0 machine defaults, 1 force inversion), please report PCI device ID, subsystem \ vendor and subsystem device ID to dri-devel@lists....

Categories: os-dev

Linux, RPi and USB over IP

Published at August 18, 2014 · Piotr Król · 10 min read

Trying to google ‘USB over IP’ doesn’t give much except some business web pages that give you it as a service. This brings some information about potential on the market IMHO. Main idea is well presented on open source project page for usbip. I really recommend to read USB/IP - a Peripheral Bus Extension for Device Sharing over IP Network technical paper it describe briefly technical details and capability. In short USB over IP is a sharing system aim to expose USB devices from server to client encapsulating USB I/O messages in TCP/IP payload....

Categories: firmware

Coreboot for QEMU armv7 (vexpress-a9) emulated mainboard

Published at August 7, 2014 · Piotr Król · 8 min read

Recently I came back to look into coreboot. Mainly because low level is fun and skills related to firmware (even coreboot) starting get attention on freelance portals (first odesk job (link removed), second odesk job). I was surprised that under the wings of Google coreboot team start to support ARM (BTW ARM programming is IMHO next great skill to learn). So I cloned latest, code compiled QEMU armv7 mainboard model and tried to kick it in latest qemu-system-arm....

Categories: firmware

Linux (Debian Wheezy) on Lenovo y510p

Published at May 16, 2014 · Piotr Król · 4 min read

After long analysis I decide to buy new laptop. I had about $1000 (or 3000PLN) and most important things to me were: i7 CPU - because of performance (of course at least 4700 series) SSD - again performance 17.3” - working space no OS/FreeDos/Linux - I will not pay additional fee to M$ for system that I won’t use Full HD resolution at least 8GB RAM non-glare display First I realize that my budget is to small for such a hardware....

Categories: os-dev

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