Edison

Building U-Boot

Build U-Boot for the Edison:

$ make edison_defconfig
$ make

This produces u-boot.bin (the raw U-Boot binary) and u-boot-edison.img (the full image, with the OSIP header that the mask ROM expects, used by the xFSTK recovery flow below).

Note

The mask ROM loads the OS image to 0x01100000 but jumps to 0x01101000, so U-Boot must sit 4KB into the loaded data. binman pads u-boot-edison.img with 4KB of zeroes ahead of U-Boot to provide this gap. The bare u-boot.bin does not contain the padding, so when flashing it directly over DFU you must prepend the 4KB yourself (see below).

There are two ways to get U-Boot onto the board:

over DFU, when the board already runs a working U-Boot – this is the normal case and needs nothing but dfu-util;
with the xFSTK downloader, when the board has no usable firmware and has to be recovered through the mask ROM.

Updating U-Boot over DFU

Once a working U-Boot is present, updating it is just a DFU transfer into the u-boot0 eMMC partition; the board boots the new U-Boot on the next reset.

Prepend the 4KB alignment gap to u-boot.bin:

$ { head -c 4096 /dev/zero; cat u-boot.bin; } > u-boot-edison-dfu.bin

Reset the board, interrupt autoboot to reach the U-Boot prompt and start DFU:
```
=> run do_dfu_alt_info_mmc
=> dfu 0 mmc 0
```
U-Boot also opens this window automatically for a few seconds during boot (see dfu_to_sec and do_probe_dfu in the environment), so a host can flash without stopping at the prompt.

From the host, write the image to the u-boot0 partition:

$ dfu-util -d 8087:0a99 --alt u-boot0 -D u-boot-edison-dfu.bin

Stop DFU on the board (Ctrl+C) and reset:
```
=> reset
```

Recovering a board with xFSTK

Use this when the board has no usable U-Boot – a blank or bricked board, or to install U-Boot for the first time. It reflashes both the Intel firmware (IFWI) and U-Boot through the mask ROM, so it needs the Edison recovery image (the DNX and IFWI blobs) in addition to u-boot-edison.img.

A board with no valid firmware drops into the mask ROM’s DnX download mode (USB ID 8086:e005) automatically on power-up; no recovery straps are needed for that. The FM/RM straps only force an otherwise-healthy board into recovery.

You need the xfstk-dldr-solo tool. If your distribution does not package it, build it from the xFSTK sources:

cd xFSTK
export DISTRIBUTION_NAME=ubuntu20.04
export BUILD_VERSION=1.8.5
git checkout v$BUILD_VERSION
...

Copy xfstk-dldr-solo to /usr/local/bin and libboost_program_options.so.1.54.0 to /usr/lib/i386-linux-gnu/. You might find this drive helpful for the recovery image and the libraries.

Download and unpack the Edison recovery image, then, with the board powered off, run:

xfstk-dldr-solo --gpflags 0x80000007 \
    --osimage u-boot-edison.img \
    --fwdnx recover/edison_dnx_fwr.bin \
    --fwimage recover/edison_ifwi-dbg-00.bin \
    --osdnx recover/edison_dnx_osr.bin

and power-cycle the board within about 10 seconds. To check that the board is in download mode, look for the mask ROM:

$ lsusb | grep -E "8087|8086"
Bus 001 Device 004: ID 8086:e005 Intel Corp.

The tool flashes the firmware and U-Boot and the board resets. Within a few seconds U-Boot starts, and once the DFU alt list appears (USB ID 8087:0a99) the board is ready for the DFU updates described above.

Note

To run dfu-util and xfstk-dldr-solo without sudo, add udev rules granting access to the Edison USB IDs, for example:

SUBSYSTEM=="usb", ATTR{idVendor}=="8086", ATTR{idProduct}=="e005", MODE="0666"
SUBSYSTEM=="usb", ATTR{idVendor}=="8087", ATTR{idProduct}=="0a99", MODE="0666"