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Return to U-boot-gena2x.

Personal tools

I decided to put my version of u-boot here, along with short FAQ and list of known bugs. Please feel free to add your bugs or questions here.

Current version of u-boot fully support uploading and downloading via dfu, booting any know distro, fully configurable, and has no known grave bugs.

List of changes

This version of u-boot is based on openmoko's stable branch of u-boot. Git can be viewed here.

Significant patches are:

Version 2:

  • GPS is not powered up on boot
  • Leave all serial ports setup to kernel

Version 1:

  • 2-4-2 timings
  • GPS should work after resume


Public freerunners should have same bootloader (board v5 and later). Latest binary version is here [1].

to use u-boot as NAND bootloader, you should flash binary to special partition:

sudo dfu-util -a u-boot -D u-boot_g2x_2.udfu

How to setup

NAND uboot occupies 2 partitions on NAND, one partition for u-boot itself and one for it's configuration.

To setup u-boot, easiest way is to edit simple text file on your host and then upload it to your phone with dfu-util.

Sample text config may be found here. This version support various kind of boot options in menu. You may use it as sample for your config.

If you switching from qi, just run boot your distro with Qi, do cat /proc/cmdline and compare/update parameters in config file.

Then you edited config file to fit your needs, you should prepare it (this adds crc):

get from [2] and run:

./ -s 262144 -f >

then flash resulting file:

sudo dfu-util -a u-boot_env -D

Useful kernel options

option description
root=/dev/mmcblk0p2 rootfs is second partition on SD card
root=/dev/mtdblock6 rootfs is on usual location on NAND
rootwait need for booting from SD. force kernel to delay boot until sd card will be ready. better than older rootdelay=
panic=20 on kernel crash, reboot automatically after 20 second delay. useful for lindi's ramconsole patch
hardware_ecc=1 use hardware ecc support for NAND, this is not defaut option use only if your rootfs NAND is flashed not with rootfs, but with direct copy from sd. this speeds up NAND read on zlib-compressed ubi by 8%.
rootfstype=XX need if your rootfs is ext2 to force kernel to use ext2 driver not ext3. use if kernel can't detect partition type
ubi.mtd=6,2048 claim 6th mtd partition as ubi layer with 2048 page align
rootflags=compr=zlib,no_chk_data_crc mount options of rootfs, use no_chk_data_crc to speed up ubifs by 8%
mem=127M reserve 1Mb if you using lindi's ramcomsole patch

How to use

By default if you press 'power' button the "bootcmd" from your config is executed, so setup it accordingly to you default distribution.

To see boot menu and select needed boot method, hold 'power', wait 1 second and hold 'aux', wait 1 more second and release both.

Known bugs

I am working to fix this bugs now:

  • sd reads correct data only 50% of times, so sd boot
  • NAND hw ecc is not supported
  • u-boot can't boot system if battery fully discharged (workaround exist)