When performing a Linux installation, the installer is often composed of a kernel and modules. These modules are often tied into the particular kernel by way of version numbers or version strings. Occasionally it is necessary to fix an installation module, update it, or provide a new one. Also similarly, if the installation kernel has a bug, then it may be necessary to provide an updated installation kernel.
The problem comes in that if you rebuild a kernel or a module, then the version strings change. Because of this change then the old and new will no longer work together. To force a new/updated kernel to work with existing modules, then use the following script: kernel-fixup.sh. To force a new/updated module to work with the existing installation kernel, then use the following script: module-fixup.sh.
The alternative to this is to generate a new kernel and module files and then rebuild the ISO media, along with all the supporting installation components. Because that much work is not necessary, then just use the fixup script.
Often, by using the fixup scripts, only a new boot disk or driver disk needs to be created in order to provide the changes. This is a far difference in size when compared with remaking a complete ISO image (650MB).