====== Tips for ODROID-C2 ======
This page introduce you an useful tips to use **ODROID-C2**.
----
====== How to change HDMI output resolution ======
**ODROID-C2** can support various resolution on HDMI output, you can select one of supported resolutions for your display (LCD monitor or TV).
<WRAP left round tip 70%>
Please make sure the resolution you select can be supported by your display before you start. Otherwise you would be hard to recover the resolution again.
</WRAP>
<WRAP center round box 60%>
Supported resolutions at this moment (2016-08-03)
  - 4K UHD (2160p)
  - 3440x1440
  - 2560x1600
  - 2560x1440
  - 2560x1080
  - 1920x1200 (WUXGA)
  - 1920x1080 (1080p)
  - 1280x720 (720p)
  - 720x480 (480p)
  - 720x576 (576p)
  - 1280x800 (800p for ODROID-VU)
  - 1280x1024 (SXGA)
  - 1024x768 (XGA)
  - 800x480 (WVGA, DVI supported for ODROID-VU7)
  - 640x480 (VGA)
  - 1680x1050
  - 1600x1200
  - 1600x900
  - 1440x900
  - 1360x768
  - 1024x600 (DVI supported for ODROID-VU7+)
  - 800x600

</WRAP>

===== Android =====
We provide you a simple but useful application, **ODROID Utility**. This helps you to change the resolution by menu as below and you can select one of them for your display. Once you select one, click the button **Apply and Reboot**. Then your **ODROID-C2** will restart with new resolution.

{{:en:odroidc2_screen.png?800|}}

===== Linux / Ubuntu =====
Coming soon...
===== Lowlevel Change =====
This section introduce you to change the resolution by manual, this would be helpful if you are failure to change the resolution and not able to sett the face of **ODROID-C2**.

The fact what initiate the resolution is from **U-boot** and the environment key is **hdmimode**. Probably your U-boot would have the one like this by default.
<code>
odroidc#print hdmimode
hdmimode=720p60hz
</code>
This will be passed to Linux kernel by **bootargs** just before Linux kernel is started. Here is the default value of **bootcmd** which starts Linux kernel. As you see, **hdmimode** is passing as boot argument.
<code>
odroidc2# print bootcmd
bootcmd=cfgload; setenv bootargs root=/dev/mmcblk0p2 rw init=/init rootwait console=ttyS0,115200 hdmimode=${hdmimode}
hdmitx=${cecconfig} logo=osd1,loaded,${fb_addr},${hdmimode} androidboot.hardware=odroidc2 androidboot.serialno=${fbt_id#}
androidboot.selinux=disabled;showlogo ${hdmimode}; movi read dtb 0 0x1000000; movi read boot 0 0x20000000;
booti 0x20000000 - 0x1000000

</code>
==== How to change the value of hdmimode ====
There are three ways to change **hdmimode** to change the resolution, you can replace **1080p60hz** with the other resolution you wish to change for your display.
And only the way with adjusting hdmimode arg value in boot.ini is available for ODROID-C2 so far, the other ways are in progress. 

=== U-boot ===
Currently, 720p60hz mode is fixed on U-Boot stage after power-on and reset.
But you can change hdmimode temporarily using 'showlogo' command.
<code>
showlogo 1080p60hz
</code>
=== Boot.ini ===
You can boot with **boot.ini** without changing U-boot environment values permanently. If **boot.ini** is existed in FAT partition **ODROID-C2** does boot with it first, unless boot with default setting stored in U-boot environment.
The example related to display is as following.

<code>
setenv hdmimode "720p60hz"

# CEC Configuration
setenv cecconfig "cecf"

# HDMI/DVI Mode Configuration
# This will enforce the signal type of display
# "hdmi" - For HDMI interface
# "dvi" - For DVI interface
setenv vout_mode "hdmi"

setenv bootargs "${rootopt} ${consoleopt} hdmimode=${hdmimode} hdmitx=${cecconfig} vout=${vout_mode} overscan_top=${top} overscan_left=${left} overscan_bottom=${bottom} overscan_right=${right} logo=${logoopt} ${androidopt} ${selinuxopt}"

showlogo ${hdmimode}

</code>
====== How to change U-boot configuration by BOOT.INI ======
----
In order to support easy boot loader setup, ODROID-C2 also support **boot.ini** as previous ODROID boards. So you can easily list up the commands what you want to executed in U-boot rather than the default. Here is the example to boot Ubuntu.

You can download the file below and copy into your FAT partition.

=== Android boot.ini example ===
<file ini boot.ini>
ODROIDC2-UBOOT-CONFIG

setenv dtbaddr 0x1000000
setenv loadaddr 0x20000000

# Resolution Configuration
# 'hdmimode' must be one of below to configure display resolution within
# supported by your TV or monitor.
#    Symbol             | Resolution
# ----------------------+-------------
#    "480p60hz"         | 720x480 Progressive 60Hz
#    "576p50hz"         | 720x576 Progressive 50Hz
#    "720p60hz"         | 1280x720 Progressive 60Hz
#    "720p50hz"         | 1280x720 Progressive 50Hz
#    "1080p60hz"        | 1920x1080 Progressive 60Hz
#    "1080p50hz"        | 1920x1080 Progressive 50Hz
#    "1080p30hz"        | 1920x1080 Progressive 30Hz
#    "1080p24hz"        | 1920x1080 Progressive 24Hz
#    "1080i60hz"        | 1920x1080 Interlaced 60Hz
#    "1080i50hz"        | 1920x1080 Interlaced 50Hz
#    "2160p60hz"        | 3840x2160 Progressive 60Hz
#    "2160p50hz"        | 3840x2160 Progressive 50Hz
#    "2160p30hz"        | 3840x2160 Progressive 30Hz
#    "2160p25hz"        | 3840x2160 Progressive 25Hz
#    "2160p24hz"        | 3840x2160 Progressive 24Hz
#    "2160p60hz420"     | 3840x2160 Progressive 60Hz YCbCr 4:2:0
#    "2160p50hz420"     | 3840x2160 Progressive 50Hz YCbCr 4:2:0
#    "640x480p60hz"     | 640x480 Progressive 60Hz
#    "800x480p60hz"     | 800x480 Progressive 60Hz
#    "800x600p60hz"     | 800x600 Progressive 60Hz
#    "1024x600p60hz"    | 1024x600 Progressive 60Hz
#    "1024x768p60hz"    | 1024x768 Progressive 60Hz
#    "1280x800p60hz"    | 1280x800 Progressive 60Hz
#    "1280x1024p60hz"   | 1280x1024 Progressive 60Hz
#    "1360x768p60hz"    | 1360x768 Progressive 60Hz
#    "1440x900p60hz"    | 1440x900 Progressive 60Hz
#    "1600x900p60hz"    | 1600x900 Progressive 60Hz
#    "1680x1050p60hz"   | 1680x1050 Progressive 60Hz
#    "1920x1200p60hz"   | 1920x1200 Progressive 60Hz
setenv hdmimode "720p60hz"

setenv rootopt "root=/dev/mmcblk0p2 rw init=/init rootwait"
setenv consoleopt "console=ttyS0,115200"
setenv androidopt "androidboot.hardware=odroidc2 androidboot.serialno=${fbt_id#}"
setenv logoopt "osd1,loaded,${fb_addr},${hdmimode}"
setenv selinuxopt "androidboot.selinux=disabled"

# HDMI/DVI Mode Configuration
# This will enforce the signal type of display
# "hdmi" - For HDMI interface
# "dvi" - For DVI interface
setenv vout_mode "hdmi"

# HPD enable/disable option
setenv disablehpd "false"

# Overscan offset configuration
# All offsets are zero and can be tuned by manual or ODROID Utility
setenv overscan_top "0"
setenv overscan_left "0"
setenv overscan_bottom "0"
setenv overscan_right "0"

setenv bootargs "${rootopt} ${consoleopt} hdmimode=${hdmimode} hdmitx=${cecconfig} vout=${vout_mode} disablehpd=${disablehpd} logo=${logoopt} ${androidopt} ${selinuxopt}"
save

showlogo ${hdmimode}

movi read dtb 0 ${dtbaddr}
movi read boot 0 ${loadaddr}
booti ${loadaddr} - ${dtbaddr}
</file>

=== Linux boot.ini example ===

(in progress)
===== Board Identifier =====
This is the keyword to identify the correct **BOOT.INI** as per board. For **ODROID-C2**, any **BOOT.INI** must contain **ODROIDC2-UBOOT-CONFIG** and other commands must be below this.
===== U-boot commands =====
You can describe multiple commands of U-boot from the next line of **ODROIDC2-UBOOT-CONFIG**. The commands are only restricted within the commands enabled by the running U-boot.

====== How to replace booting logo ======
**ODROID-C2** can show booting logo on the display till target O/S is started.

Please refer to the following wiki page.

http://odroid.com/dokuwiki/doku.php?id=en:c2_bootlogo