How to change I2C speed

[scorpiochang]

Hi chobio

You need to build uboot by self.
https://github.com/TinkerBoard/debian_u-boot?files=1

[Linux]
Building image:
$ cd debian_u-boot
$ make CROSS_COMPILE=arm-linux-gnueabihf- O=miniarm-rk3288 tinker-rk3288_defconfig all -j4
$ ./miniarm-rk3288/tools/mkimage -n rk3288 -T rksd -d miniarm-rk3288/spl/u-boot-spl-dtb.bin u-boot.img
$ cat miniarm-rk3288/u-boot.bin >> u-boot.img

Flash uboot image:
Prepare one sdcard which has the full Debian image inside.
then insert the sdcard into a linux based OS, and suppose the block device of the sdcard is /dev/sdx
$ sudo dd if=[path]/u-boot.img of=/dev/sdx seek=64

Please backup flash firstly, and be careful with dd operation.
How to backup sdcard: 
https://tinkerboarding.co.uk/forum/thread-900.html