1. Requiremets
   1. Download Ubiquiti GPL Archive: https://www.ubnt.com/download/edgemax/edgerouter-x-sfp/default/edgerouter-er-xer-x-sfpep-r6-firmware-v180
   2. Download Buildroot 2016.02: https://buildroot.org/download.html
   3. Download batman-adv, batctl and alfred sources: https://downloads.open-mesh.org/batman/releases
   4. Install u-boot-tools binfmt-support qemu qemu-user-static debootstrap lzma-alone
2. Build MIPS Toolchain
   1. Extract buildroot and change to extracted folder
   2. make menuconfig

• • Target
    • Target Architecture = MIPS (little endian)
    • Target Architecture Variant = mips 32r2
    • Use soft-float = True
  • Build option
    • Host dir = /opt/buildroot/2016.02
      • needs to be created manually
  • Toolchain
    • GCC compiler Version = gcc 4.9.x

6. 6. make
7. Crosscompile Kernel
   1. Extract Ubiquiti sources
   2. Change to extracted folder (usually ./sources)
   3. extract kernel sources and change to extraced folder
   4. replace .config with https://gist.github.com/belzebub40k/5f3d7cb946a19d5271823f81cd28f8a7#file-kernel-config-ffmwu
   5. sadly the supplied kernel only supprts gzip as output format so we need to patch it

• • • download https://gist.github.com/belzebub40k/5f3d7cb946a19d5271823f81cd28f8a7#file-mips-more-uimage-options-patch
    • patch -p1 < path/to/patchfile

6. 6. append MIPS Toolchain to $PATH

• • • export PATH=$PATH:/opt/buildroot/2016.02/usr/bin

7. 7. Build kernel/u-boot image

• • • make ARCH=mips CROSS_COMPILE=mipsel-linux- uImage.lzma

8. 8. Boot image via TFTP

• • • Setup TFTP server and copy uImage to root folder
    • Connect USB to TTL adapter: https://wiki.openwrt.org/toh/ubiquiti/ubiquiti_edgerouter_x_er-x_ka#photos
    • Parameters: 57600 8N1
    • Press '4' during boot to get u-boot prompt
    • set your IP address to to the one defined in u-boot serverip or modify it (if you modifiy it also modify u-boots own address in ipaddr to the same subnet)
    • boot uImage
      • tftpboot ${fileaddr} uImage.lzma
      • bootm

4. Crosscompile batman-adv
   1. extract source tarball and change to extracted folder
   2. build with UBNT kernel sources

• • • KERNELPATH needs to be set to the folder from 3.3.
    • make ARCH=mips KERNELPATH=~/tmp/source/kernel

3. 3. copy ./net/batman-adv/batman-adv.ko to EdgeOS
   4. load module

• • • sudo insmod ./batman-adv.ko

5. Crosscompile userland applications
   1. Debootstrap Debian Wheezy MIPSel

• • • debootstrap --foreign --arch mipsel wheezy debian_armel_wheezy http://ftp.debian.org/debian/
    • cp /usr/bin/qemu-mipsel-static debian_mipsel_wheezy/usr/bin/
    • LC_ALL=C chroot debian_mipsel_wheezy/
    • /debootstrap/debootstrap --second-stage
    • apt-get install build-essential pkg-config

2. 2. Build packages as described in their READMEs

• try to compile with similar toolchain as Ubiquiti does (buildroot-2012.11.1 gcc 4.6.x)
  • currently it does not compile under Debian 8 because gcc4.6 is to old
  • should work with Debian 7 (debootstrap + chroot)
• integrate in EdgeOS
  • http://vyos.net/wiki/Configuration_mode_templates
  • https://github.com/vyos/vyatta-dummy
• generate modified firmware images

Link to the Pad