Setup of development environment
1] Create a VirtualBox VM for Debian 7.2.0 i386. I allocated 1024MB of RAM to it. As for the virtual hard drive space, I allocated 8GB. I also recommend that you disable audio support for the VM.
2] Download the Net Install ISO image for Debian 7.2.0 i386. Boot the mentioned ISO in the VirtualBox VM you've created. I used the "Install" option in the installer boot menu.
3] This set of instructions will work with everything deselected under "Software selection." You may select software to your taste during installation.
4] After the installation, the guest OS will automatically get an IP Address via DHCP.
5] As root in your guest OS:
# apt-get update
# apt-get upgrade
6] Install OpenSSH client and server software as root in your guest OS if this will make file transfers and access to your development environment convenient for you:
# apt-get install openssh-client openssh-server
7] As root in your guest OS:
# apt-get install ncurses-dev uboot-mkimage build-essential git
# cd ~
# wget http://www.malaya-digital.org/gcc-linaro-arm-linux-gnueabihf-4.7-2013.01-20130125_linux.tar.bz2
# tar xjfv gcc-linaro-arm-linux-gnueabihf-4.7-2013.01-20130125_linux.tar.bz2
8] Add toolchain directory to $PATH in your guest OS(You may want to add this to /etc/profile . Appending it will do.):
export PATH=/root/gcc-linaro-arm-linux-gnueabihf-4.7-2013.01-20130125_linux/bin:$PATH
9] Restart your guest OS as root:
# shutdown -r now

Compiling the kernel (Copied from http://olimex.wordpress.com/2013/06/19/building-linux-for-a10s-from-scratch/ and http://olimex.wordpress.com/2013/10/28/building-debian-sd-card-for-linux-with-kernel-3-4-from-scratch-for-a10s-olinuxino-micro/ with some modifications)
1] In the development environment you've made above, login as root. Then get the kernel source code:
# cd ~
# git clone https://github.com/linux-sunxi/linux-sunxi
2] Note that I'm using the revision below(this is the latest revision for the 3.4.61 kernel):
# cd ~/linux-sunxi/
# git rev-parse --verify HEAD
01d42bfbd0ab3f42205ba1d3f266840bbf14098a
So, to checkout the mentioned revision:
# cd ~/linux-sunxi/
# git checkout 01d42bfbd0ab3f42205ba1d3f266840bbf14098a
3] Do a "make mrproper":
# cd ~/linux-sunxi
# make mrproper
4] Download a10s_defconfig:
# cd ~/linux-sunxi
# wget http://www.malaya-digital.org/a10s_defconfig
Move this file to ~/linux-sunxi/arch/arm/configs/ . These are to be done in your development environment as root:
# mv a10s_defconfig ~/linux-sunxi/arch/arm/configs/
5] Execute the following under the linux-sunxi directory in your development environment as root:
# cd ~/linux-sunxi/
# make ARCH=arm a10s_defconfig
6] Configure the kernel in your development environment as root:
# make ARCH=arm menuconfig

HINT: If you're having problems with Logitech wireless keyboards and mice, don't build this (for Linux 3.4.61):
Device Drivers->HID Devices->Special HID drivers->< > Logitech Unifying receivers full support

HINT: To verify OTG is enabled(for Linux 3.4.61):
Under Kernel Configuration, this must be built in the kernel:
Device Drivers->USB support->[*] SUNXI USB2.0 Dual Role Controller Support
Also, this must be built in the kernel, too:
Device Drivers->USB support->SUNXI USB2.0 Dual Role Controller Support->[*] SUNXI USB2.0 Manager
And make sure of the following:
Device Drivers->USB support->SUNXI USB2.0 Dual Role Controller Support->SUNXI USB2.0 Manager->USB0 Controller support (otg support)->(X) otg support

HINT: To verify Ethernet is enabled(for Linux 3.4.61):
Under Kernel Configuration, this must be built in the kernel:
Device Drivers->Network device support->Ethernet driver support-><*> Allwinner Ethernet MAC support
7] Note that before compiling kernel, you have to patch it:
Download the patch hcd_axp-md.patch from http://www.malaya-digital.org/hcd_axp-md.patch:
# cd ~/linux-sunxi/
# wget http://www.malaya-digital.org/hcd_axp-md.patch
Copy files:
# cp drivers/usb/sunxi_usb/hcd/hcd0/sw_hcd0.c drivers/usb/sunxi_usb/hcd/hcd0/sw_hcd0a.c
# cp drivers/usb/sunxi_usb/hcd/hcd0/sw_hcd0.c drivers/usb/sunxi_usb/hcd/hcd0/sw_hcd0b.c
Apply the patch:
# patch -p0 < hcd_axp-md.patch
Copy a file again:
# cp drivers/usb/sunxi_usb/hcd/hcd0/sw_hcd0a.c drivers/usb/sunxi_usb/hcd/hcd0/sw_hcd0.c
8] Edit ~/linux-sunxi/arch/arm/plat-sunxi/include/plat/i2c.h . Find "I2C0_TRANSFER_SPEED". Define "100000" for I2C1_TRANSFER_SPEED and up. These are to be done in your development environment as root. For example, the desired edit is:

#define I2C0_TRANSFER_SPEED (400000)
#define I2C1_TRANSFER_SPEED (100000)
#define I2C2_TRANSFER_SPEED (100000)
#define I2C3_TRANSFER_SPEED (100000)
#define I2C4_TRANSFER_SPEED (100000)
9] You can now compile the kernel and its modules in your development environment as root.
# cd ~/linux-sunxi/
# make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- -j4 uImage
# make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- -j4 INSTALL_MOD_PATH=out modules
# make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- -j4 INSTALL_MOD_PATH=out modules_install
10] In your development environment, your kernel will be "~/linux-sunxi/arch/arm/boot/uImage". And your modules will be found at "~/linux-sunxi/out/lib/modules/3.x.xx" where 3.x.xx is kernel version (eg: "3.4.61+").

Compiling Uboot (Copied from http://olimex.wordpress.com/2013/06/19/building-linux-for-a10s-from-scratch/ and http://olimex.wordpress.com/2013/10/28/building-debian-sd-card-for-linux-with-kernel-3-4-from-scratch-for-a10s-olinuxino-micro/ with some modifications)
The Allwinner Linux-Sunxi community uboot is maintained by Henrik Nordstrom aka hno on Freenode irc. You can find him in #linux-sunxi or #olimex channels. If something with uboot is broken, he is your man.

1] Download the uboot sources from GitHub repository.
# cd ~
# git clone https://github.com/linux-sunxi/u-boot-sunxi

After the download, you should have a new directory.

# cd ~/u-boot-sunxi/
2] Note that I'm using the revision below:
root@debian:~/u-boot-sunxi# git rev-parse --verify HEAD
09ef3a640a3eb58e66eedcf239193e2ab548e730

So, to use the mentioned revision:

root@debian:~/u-boot-sunxi# git checkout 09ef3a640a3eb58e66eedcf239193e2ab548e730

3] Edit ~/u-boot-sunxi/include/configs/sunxi-common.h . Look for the following:

"setargs=" \
"if test -z \\\\\"$root\\\\\"; then"\
" if test \\\\\"$bootpath\\\\\" = \"/boot/\"; then"\
" root=\"/dev/mmcblk0p1 rootwait\";"\
" else" \
" root=\"/dev/mmcblk0p2 rootwait\";"\
" fi;"\
" fi;"\

Change " root=\"/dev/mmcblk0p2 rootwait\";"\" to the following:
" root=\"/dev/mmcblk0p2 ro rootwait\";"\

4] With the following command, you can start the uboot build:

# cd ~/u-boot-sunxi/
# make distclean CROSS_COMPILE=arm-linux-gnueabihf-
# make a10s-olinuxino-m CROSS_COMPILE=arm-linux-gnueabihf-
5] At the end of the process, you can check if everything is OK by:

# ls u-boot-sunxi-with-spl.bin
If you got this file, well done so far.

Format and setup the SD-card (Copied from http://olimex.wordpress.com/2013/06/19/building-linux-for-a10s-from-scratch/ with some modifications)
We suggest that you use a 4GB class 10 micro SD card. But you can use any micro SD card between 2GB and 16GB.

Also, please make sure you have a micro SD card that is "clean." By "clean," I mean that this card was not set yet before for an ARM computer. If your micro SD card is not clean, there is a good chance that it will not boot. To clean(Note that this will take plenty of time. It took me 49 minutes to complete this on a 16 GB card. Substitute "/dev/mmcblkX" appropriately for your micro SD card):

# dd if=/dev/zero of=/dev/mmcblkX

First, we have to make the correct card partitions. This is done with fdisk.

1] Plug the micro SD card into your SD card reader. Then, enter in the terminal:

# ls /dev/sd
Then press TAB twice. You will see a list of your sd devices like sda, sdb, sdc, etc. Note that some of these devices may be your hard disk, so make sure you know which one is your micro SD card before you proceed. You can damage your HDD if you choose the wrong sd device. You can do this by unplugging your micro SD card reader, and identify which “sd” devices was removed from the list.

2] Once you know which device is your micro SD card, use this text instead of the sdX name in the references below:

# fdisk -u=sectors /dev/sdX
Then do these steps:

2a] This will list your partitions:
p

2b] If there are already partitions on your card, do:
d 1
If you have more than one partitition, delete them all.

2c] Create the first partition. It should start from 2048 and end at 34815:
n p 1

2d] Create the second partition:
n p 2 enter enter

2e] List the created partitions:
p

If you did everything correctly on a 4GB card, you should see something like:

Disk /dev/sdX: 3980 MB, 3980394496 bytes
123 heads, 62 sectors/track, 1019 cylinders, total 7774208 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Device Boot Start End Blocks Id System
/dev/sdg1 2048 34815 16384 83 Linux
/dev/sdg2 34816 7774207 3869696 83 Linux

2f] Write changes to the micro SD card.
w

3] Now, we have to format the file system on the card:

The first partition should be vfat as this is the FS which the Allwinner bootloader understands.

# mkfs.vfat /dev/sdX1

4] The second partition should be a normal Linux EXT4 FS:

# mkfs.ext4 /dev/sdX2

Installing the kernel, Slackware ARM 14.0 mini root filesystem, and kernel modules
1] Proceed to copy the "~/linux-sunxi/arch/arm/boot/uImage" kernel you've compiled in the development environment into the first filesystem of the micro SD card.
Mount the first partition:
# mkdir /mnt/olinuxino0
# mount /dev/sdX1 /mnt/olinuxino0 # Substitute the appropriate value for X in /dev/sdX1

Then copy the kernel uImage to the first filesystem of the micro SD card.
# cp uImage /mnt/olinuxino0 # Get the uImage file from the environment you've compiled the kernel.
2] Copy the script.bin file in /mnt/olinuxino0 . The mentioned file can be found here: https://drive.google.com/file/d/0B-bAEPML8fwlYkItdU1TTm1VN0E/edit?usp=sharing
--OR--
If you need to compile your own script.bin, you can get the fex files here in a scripts_A10s.7z archive: https://drive.google.com/file/d/0B-bAEPML8fwlY3llVDJxelY3d28/edit?usp=sharing
3] Unmount /mnt/olinuxino0 :
# umount /mnt/olinuxino0
4] Mount the second partition:
# mkdir /mnt/olinuxino1
# mount /dev/sdX2 /mnt/olinuxino1 # Substitute the appropriate value for X in /dev/sdX1
5] Extract the Slackware ARM 14.0 mini root filesystem in /mnt/olinuxino1 . Slackware mini root filesystem can be found here: ftp://ftp.arm.slackware.com/slackwarearm/slackwarearm-devtools/minirootfs/roots
6] Delete all contents of /mnt/olinuxino1/dev/*
7] Extract this file in /mnt/olinuxino1/dev : http://www.malaya-digital.org/dev.tar.gz
8] Proceed to copy the generated kernel modules ("~/linux-sunxi/out/lib/modules/3.x.xx" in the development environment where you've compiled the kernel) in the second filesystem of the micro SD card.

If the /mnt/olinuxino1/lib/modules directory does not exist, create it.
# mkdir /mnt/olinuxino1/lib/modules
# cp -rf 3.x.xx+ /mnt/olinuxino1/lib/modules # Get the modules directory from the environment you've compiled the kernel.
9] Append the following in /mnt/olinuxino1/etc/fstab:
/dev/mmcblk0p2 / ext4 errors=remount-ro 0 1
10] Unmount /mnt/olinuxino1 :
# umount /mnt/olinuxino1

Write Uboot (Copied from http://olimex.wordpress.com/2013/06/19/building-linux-for-a10s-from-scratch/ with some modifications)

Note that you have to write u-boot-sunxi-with-spl.bin in /dev/sdX (not sdX1 or sdX2).

# dd if=u-boot-sunxi-with-spl.bin of=/dev/sdX bs=1024 seek=8
# sync

NB: When you boot OLinuXino using the micro SD card with Slackware 14.0 for ARM, the "root" user has the password "password" by default.