The method described here allows you to modify the root filesystem of a TC/MC system without actually modifying the tinycore.gz/microcore.gz files. This is particularly useful when you want your remaster to work with a new version of TC/MC or if you for some other reason want to remaster the root filesystem without having to modify the root filesystem files shipped by TC/MC.
The method is based on the capability of the syslinux family bootloaders (syslinux, isolinux, extlinux, pxelinux) to load multiple initramfs images during boot. If you are using Grub you could still use this method by chainloading from Grub to a syslinux family bootloader. It is also possible to pass multiple initramfs images to linux from grub directly, as well as from iPXE / gPXE.
The description here is based on the use of extlinux (since I use this to boot from an ext2 partition), however the same configuration should be possible to use for other syslinux family bootloaders.
In order to install extlinux to your boot partition you need have the TC
syslinux.tcz extension installed on your system and the boot partition mounted. My boot partition is mounted under
/mnt/hda1 and I install extlinux at
To install extlinux you do:
sudo extlinux -i /mnt/hda1/boot/extlinux
This will make the file
extlinux.sys appear in the installation directory. (Mount the device manually: “mount /dev/xxx /mnt/xxx”. Using the mount tool provided by tinycore extlinux will give you an error (it can't install to devices mounted with loop).
In case extlinux is the only bootloader on your system, you need to update the MBR of the boot device (note that if you are using grub and want to keep it that way DO NOT perfom the following action). To update the MBR
sudo cat /usr/local/lib/syslinux/mbr.bin > /dev/XXX
/dev/XXX is the appropriate master device (in my case
To be able to use the menu features of the syslinux family bootloaders you should:
sudo cp /usr/local/lib/syslinux/vesamenu.c32 /mnt/hda1/boot/extlinux
extlinux operates according to a configuration file called
extlinux.conf and this file should be located in the extlinux installation directory (
The content of this file should look something like:
default vesamenu.c32 menu title My Boot Options timeout 200 prompt 0 ontimeout mc_original label my_remaster menu label Microcore with remaster kernel /boot/vmlinuz initrd /boot/core.gz,/boot/my_initramfs.gz append base label mc_original menu label Microcore without remaster kernel /boot/vmlinuz initrd /boot/core.gz append base menu width 80 menu margin 10 menu rows 12 menu tabmsgrow 18 menu endrow 24 menu timeoutrow 20
The core part for the remaster function is the line:
This tells extlinux to load both
my_initramfs.gz and create a root file system that is the combination of the two.
The remaster content should be packed into a gzipped cpio archive. What it should contain is up to you. We here show an example where a couple of TC/MC extensions are placed at
/opt/tce/optional. During startup TC/MC will load any extension found in the list
First you need to create a working directory that represents the root of the initramfs to be created:
$ mkdir my_root $ cd my_root
Now create the directory where the extensions are going and copy the extensions to that directory:
$ mkdir -p opt/tce/optional $ cp /path_to_extensions/xxx.tcz opt/tce/optional $ cp /path_to_extensions/yyy.tcz opt/tce/optional $ . $ . $ ls -1 opt/tce/optional > opt/tce/onboot.lst
Once all files to be included into the root filesystem are in place, it is time to create the archive and copy it to the boot partition.
In case you are using Grub as your boot loader you could follow the instructions above (except for updating of the MBR) and then create an entry like the following in your Grub configuration:
title EXT-CHAIN root (hd0,0) makeactive chainloader +1
When you boot via grub you just select the boot entry named
EXT-CHAIN and that would continue the boot process using your extlinux setup. Note that you might need to change
(hd0,0) to something that fits your system.
gPXE/iPXE are capable of passing multiple initramfs images to the kernel as well. The following example gPXE script will download
some.server and pass both of them to Linux to be unpacked on boot:
#!gpxe kernel http://some.server/vmlinuz initrd http://some.server/core.gz initrd http://some.server/my_initramfs.gz boot