7.2.3. Preparing an initial RAM disk update

Advanced procedure

This is an advanced procedure that you should consider only if you cannot perform a driver update with any other method.

The Red Hat Enterprise Linux installation program can load updates for itself early in the installation process from a RAM disk — an area of your computer's memory that temporarily behaves as if it were a disk. You can use this same capability to load driver updates. To perform a driver update during installation, your computer must be able to boot from a preboot execution environment (PXE) server, and you must have a PXE server available on your network. Refer to Chapter 34, PXE Network Installations for instructions on using PXE during installation.

To make the driver update available on your PXE server:

Place the driver update image file on your PXE server. Usually, you would do this by downloading it to the PXE server from a location on the Internet specified by Red Hat or your hardware vendor. Names of driver update image files end in .iso.
Copy the driver update image file into the /tmp/initrd_update directory.
Rename the driver update image file to dd.img.
At the command line, change into the /tmp/initrd_update directory, type the following command, and press Enter:
```
find . | cpio --quiet -c -o | gzip -9 >/tmp/initrd_update.img
```
Copy the file /tmp/initrd_update.img into the directory the holds the target that you want to use for installation. This directory is placed under the /tftpboot/pxelinux/ directory. For example, /tftpboot/pxelinux/r5su3/ might hold the PXE target for Red Hat Enterprise Linux 5.3 Server.
Edit the /tftpboot/pxelinux/pxelinux.cfg/default file to include an entry that includes the initial RAM disk update that you just created, in the following format:
```
label target-dd
kernel target/vmlinuz
append initrd=target/initrd.img,target/dd.img
```
Where target is the target that you want to use for installation.

Example 7.1. Preparing an initial RAM disk update from a driver update image file

In this example, driver_update.iso is a driver update image file that you downloaded from the Internet to a directory on your PXE server. The target that you want to PXE boot from is located in /tftpboot/pxelinux/r5su3

At the command line, change to the directory that holds the file and enter the following commands:

$ cp driver_update.iso /tmp/initrd_update/dd.img
$ cd /tmp/initrd_update
$ find . | cpio --quiet -c -o | gzip -9 >/tmp/initrd_update.img
$ cp /tmp/initrd_update.img /tftpboot/pxelinux/r5su3/dd.img

Edit the /tftpboot/pxelinux/pxelinux.cfg/default file and include the following entry:

label r5su3-dd
kernel r5su3/vmlinuz
append initrd=r5su3/initrd.img,r5su3/dd.img

Refer to Section 7.3.5, “Select a PXE target that includes a driver update” to learn how to use an initial RAM disk update during installation.