initramfs research

Reading list

• initramfs: an overview 
• initramfs page at Debian Wiki  
• SourceMage initramfs HowTo 
• man mkinitramfs

Background

I am assuming the N2200 cannot boot any kernel above 2.6.24 (basis: others have tried and failed). This kernel will be my starting-point. It supports initramfs, which has the advantage of being built into the kernel. All the N2200 can do is load a kernel and pass control over to it. It cannot even pass command-line parameters to the kernel, although it is possible to patch the kernel to hard-code command-line parameters.

One painful experience was my attempt to get a patched kernel 2.6.18 to boot to root-on-NFS using hard-coded command-line parameters. Theoretically, this should be possible, but I couldn't get it to work ("Root-NFS: Server returned error -13").

My next gambit is to prepare and compile a new kernel (2.6.24) with a built-in initramfs containing BusyBox.

Tools

• mkinitramfs – This tool is installed by default in the vanilla Debian system. When using it for development, we have to be careful to override the default settings (in /etc/initramfs-tools/initramfs.conf) because mkinitramfs is also used by the Debian system itself and we don't want to mess that up!