# update-uboot: Self-contained, Online u-boot updater

update-uboot is a completely self-contained way to update u-boot. The generated binary includes the updated u-boot binary *and* Linux kernel module to allow
rw access to the (often protected) /dev/mtd0 partition.

## Installation

1. Install zig (https://ziglang.org/download/)

  - Requires sentinel-terminated slices, only in master (as of 2020-01-13) or 0.6.0+

2. `git clone https://git.sr.ht/~monadnock/zig-mtd`

3. `zig build`

## Modification

This code only currently supports mipsel out of the box. The only parts specific to mipsel are:

 - *mtd-rw.ko*; The embedded kernel module is compiled for mipsel. You can replace this file with a version compiled for your arch, or comment out the function if you don't require it.
 - *uboot-feb2019.bin*: Same story. This is the version of u-boot I needed for mt7628 product. You'll almost certainly want to replace this file. Ask your doctor what version of u-boot is right for you
 - The [ioctl numbers used to ERASE and UNLOCK the mtd](https://git.sr.ht/~monadnock/zig-mtd/tree/master/src/mtd.zig#L8) are arch specific

    zig couldn't grok the nested ioctl #define horrors from the mtd headers. The easiest way I've found to determine these magic numbers is to compile the mtd-magic.c file in the repo with your target toolchain and run it on the target. It'll print out the macro expansions (e.g. `mipsel-openwrt-linux-gcc -o mtd-magic mtd-magic.c`)