I am going to rebuild initial ramdisk image.
I am not sure following is right:

# cp initrd-2.1.21-1.3194.fc7.img initrd-2.1.21-1.3194.fc7.img.gz
# gunzip initrd-2.1.21-1.3194.fc7.img.gz
# mount -t ext3 -o loop initrd-2.1.21-1.3194.fc7.img /mnt/temp
mount: wrong fs type, bad option, bad superblock on /dev/loop0,
missing codepage or other error
In some cases useful info is found in syslog - try
dmesg | tall or so

In syslog, message is like this: "VFS: Can't find ext3 filesystem on
dev loop0".

Also follows:
# cd /mnt/temp
# mkdir initrd
# gunzip < /boot/initrd-2.6.21-1.3194.fc7.img > inittest.img
# mount -o loop inittest.img initrd
mount: you must specify the filesystem type

# mount -t ext3 -o loop inittest.img initrd
mount: wrong fs type, bad option,...[Same messages with my first mount

Oh, I am afraid.
Other many methods don't help me also.

How can change initial ramdisk's contents?
How can mount initrd image?
What is other method for initrd?

Please answer to me.

Good your day.
Thank you.