I have already tried, without --format=lzma it fails to boot. -Mike On Wed, 2018-01-31 at 17:10 +0000, Nux! wrote: > Don't archive as lzma if you don't want lzma, remove the " > --format=lzma" parameter. > > hth > Lucian > > -- > Sent from the Delta quadrant using Borg technology! > > Nux! > www.nux.ro > > ----- Original Message ----- > > From: "Mircea Husz" <mirceahusz at yahoo.com> > > To: "CentOS mailing list" <centos at centos.org> > > Sent: Wednesday, 31 January, 2018 16:51:20 > > Subject: [CentOS] How is initrd.img packed and compressed? > > Hi, > > > > In order to work around a known upstream bug I needed to add a udev > > rule to pxeboot initrd.img on CentOS 7. > > > > The process is straightforward: > > 1 - extract the pxeboot initrd.img to a new directory > > 2 - add the udev rule needed to fix the bug > > 3 - pack and compress it back in initrd.img format > > > > The resulting updated image works, it fixes the upstream bug and > > life > > is good. But although it works, it's not > > the same format as the original initrd.img that ships with the > > distro. > > I would like to know the proper incantation > > used to package initrd.img > > > > Now for the specifics. The original image: http://mirror.steadfast. > > net/ > > centos/7.4.1708/os/x86_64/isolinux/initrd.img > > is extracted: /usr/lib/dracut/skipcpio initrd.img | xzcat | cpio > > -i -d > > and after adding the needed udev rule, it gets packed and > > compressed as > > follows: > > > > find . 2>/dev/null | cpio --quiet -c -o | xz -9 > > --format=lzma >"~/patched-initrd.img" > > > > Now for the difference. FIrst the original distro image: > > # file initrd.img > > initrd.img: xz compressed data > > > > # file patched-initrd.img > > patched-initrd.img: LZMA compressed data, streamed > > Without the --format=lzma flag it fails to boot. > > > > Does anyone know how this is done properly ? > > > > Thanks, > > -Mike > > > > _______________________________________________ > > CentOS mailing list > > CentOS at centos.org > > https://lists.centos.org/mailman/listinfo/centos > > _______________________________________________ > CentOS mailing list > CentOS at centos.org > https://lists.centos.org/mailman/listinfo/centos