EDIT: I HAVE ANSWERED MY OWN QUESTION. MODERATOR, PLEASE FEEL FREE TO DELETE THIS THREAD.

Inside Fanoush's initfs_flasher folder, there are many .tgz files whose names suggest that they are tar-zipped initfs images for all of the Maemo OS's from OS2006 to the latest Diablo (names such as initfs.2008-43.tgz and initfs.osso-n770.2006-25.tgz). Can anyone confirm that this is indeed what they are?

EDIT: OK, I untarred one of the files and took a look at it. The answer is no, it's the linuxrc for a customized initfs (including bootmenu) corresponding to the indicated OS.

Someone was asking on another thread how he could restore the original initfs "in a single operation" after installing the bootmenu customization. Before suggesting that he can untar the appropriate .tgz file and run initfs_flash with the untarred file as argument, I had better check that this is in fact going to work.

Thanks.