Kernel panic - not syncing: junk in compressed archive

Hello all,
I'm building a linux system for a new architecture,
and I want to use initramfs support to build a filesystem.

I have seen that there are several ways to do that with initramfs.
Either the kernel will build the cpio archive for me, or I can provide an
external one with the CONFIG_INITRAMFS_SOURCE option.

An other way is to provide a configuration file to this option.

I have tried all these methods but each time, the boot stops with the
following message:

Kernel panic - not syncing: junk in compressed archive

I have googled on that but have not found relevant solution.

Does anyone know what could generally be the cause of this problem?

Thanks in advance for your help.