==== CyanogenMod 11 (KitKat) / Archlinux multiboot on Toshiba AC100 ====

=== Switching to U-Boot and Installing CyanogenMod ===
I installed CM-11 following [[https://code.google.com/p/cm-paz00/wiki/InstallGuide?tm=6]]
Completing the process, you'll have also u-boot installed on your AC100 SOS partition (/dev/mmcblk0p1) !

=== Adding a new item to u-boot menu ===

Reboot your ac100 using SOS-BOOT: connect your ac100 to a PC via mini-USB cable, Press and hold CTRL+ESC+POWER keys at the same time on the ac100 and, from the pc:
  nvflash --bl sos-uboot-r5-2013-09-23.bin --go

ac100 will restart with sos kernel & minimal system.
now you can access & mount ac100 partitions:

  
  mkdir /sos
  mount /dev/mmcblk0p1 /sos
  
As you can see i used an sd to copy filesystem,kernel,modules,dtmb from. My ac100 is 16GB model, and i used mmcblk0p7 to install Archlinux.

Ok, u-boot uses a "compiled" text file to show its menu: in /sos/boot you'll find boot.scr (CM-11 gift :)) ; let's copy it in boot.cmd and modify:
  cd /sos/boot
  cp boot.scr boot.cmd
  vi boot.cmd
  
now you'll have to delete (press 'x' some times... ) the "binary garbage" header, an add (press 'i' to switch vi in edit mode) a new line; something like:

  setenv bootmenu_0 "Boot LNX ARCH =setenv bootargs 'root=/dev/mmcblk0p7 rootfstype=ext4 rootwait'; ext2load mmc 0:2 0x1000000 /boot/zImage; ext2load mmc 0:2 0x2000000 /boot/tegra20-paz00.dtb; bootz 0x1000000 - 0x2000000;"

as you can see, i put my kernel image and dtb in LNX partition (mmc 0:2); if you want to use SOS partition (if you followed CM-11 installation instructions they are both sized 64MB) replace with mmc 0:1

I wasted a lot of time figuring out how to instruct u-boot to load a kernel missing an initrd; finally i realized bootz needs two (kernel initrd) or three (kernel initrd dtb) arguments: if you have not an initrd, you must use a '-' as 2nd argument!

=== compile boot.scr ===
You must now compile boot.cmd to obtain an updated boot.scr: 
  mkimage -A arm -O linux -T script -C none -a 0 -e 0 -n "ubootscript" -d boot.cmd boot.scr


=== Copying your kernel into ac100 ===

As already stated, i used LNX partition for my kernel:

  mkdir /lnx
  mount /dev/mmcblk0p2 /lnx
  mkdir /sd # to copy kernel from
  mount /dev/mmcblk1p1 /sd

  cp /sd/zImage /lnx/boot/
  cp /sd/tegra20-paz00.dtb /lnx/boot/
  
=== Installing archlinux filesystem ===
  
Of course you'll need to format (already done during CM-11 installation) & mount your target partition
  mkdir /arch
  mount /dev/mmcblk0p7 /arch
  
and untar rootfs on it:
  cd /arch/
  tar xvf /sd/ArchLinuxARM-trimslice-latest.tar .
  
=== Copying (wifi) modules to root filesystem ===
  bzcat /sd/modules.tar | tar xvf .

=== Umounting partitions and rebooting ===
Everything should now be in it's right place... 
  cd /
  umount *
  
cross your fingers, power off and after power on your ac100! 

=== Configure ArchLinux ===
After a reboot, you can finally configure your archlinux installation.
Follow [[archlinux#arch_base_configuration]] for instructions.

=== Compiling your own kernel ===

But where can you find an up-to-date kernel for your linux?
Compile yourself your own! 
See [[kerneldev?&#mainline_git_kernel]] for instructions.