From: kaukasoina3dore73js4@sci.fi   
      
   protozoaire   wrote:   
   >initrd.img is (normally?) a gzip compressed cpio archive, known by   
   >    $ file (PathtTo)/initrd.img   
   >Example to extract all files/dirs tree in current dir:   
   >    $ gunzip -cd (PathTo)/initrd.img> | cpio -i -d -m -H newc   
   >--no-absolute-filenames   
      
   Insert the USB stick. OK, it's the 3.5G partition, /dev/sdb1 here. initrd is   
   XZ compressed. bsdtar extracts anything! 'setup' is there. You can even try   
   to run it from the extracted setup system via chroot. (Won't work correctly   
   there, of course.)   
      
   root@acer:~ # lsblk   
   NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINTS   
   sda      8:0    0 931.5G  0 disk   
   |-sda1   8:1    0 931.5G  0 part /   
   `-sda2   8:2    0  1007K  0 part   
   sdb      8:16   1  28.6G  0 disk   
   |-sdb1   8:17   1   3.5G  0 part   
   `-sdb2   8:18   1   1.4M  0 part   
   sr0     11:0    1  1024M  0 rom   
   root@acer:~ # mount -o ro /dev/sdb1 /mnt/memory   
   root@acer:~ # file /mnt/memory/isolinux/initrd.img   
   /mnt/memory/isolinux/initrd.img: XZ compressed data, checksum CRC32   
   root@acer:~ # TMPDIR=$(mktemp -d)   
   root@acer:~ # cd $TMPDIR   
   root@acer:/tmp/tmp.Pr2IHKp8O9 # bsdtar xf /mnt/memory/isolinux/initrd.img   
   root@acer:/tmp/tmp.Pr2IHKp8O9 # ls -l usr/lib/setup/setup   
   -rwxr-xr-x 1 root root 17982 2022-02-02 10:20 usr/lib/setup/setup   
   root@acer:/tmp/tmp.Pr2IHKp8O9 # chroot $TMPDIR /usr/lib/setup/setup   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)