By default Debian etch 32bit allows a maximum of 4 GB RAM. The limit can be raised up to 64 GB with a single apt-get command / kerenl update:
apt-get install linux-image-2.6-686-bigmem
That’s it, reboot your system and you will be able to install up to 64GB of RAM to your system.
Compiling the kernel from source on Debian is actually pretty simple thing to do.
This guide has been tested on standard etch installation but will probably work on other versions and debian-like operating systems. The system is easy to break if not done right, compile and install the kernel at your own risk!
Install required packages
apt-get install kernel-package libncurses5-dev fakeroot wget build-essential