Originally written: 3/19/2012; last Web page update:
-11/8/2015, referencing rEFInd 0.10.0
+3/4/2017, referencing rEFInd 0.10.5
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A kernel whose filename lacks a version string matches an initial RAM disk that also lacks a version string in its filename. Note that you can reliably use only one kernel and initial RAM disk per directory that lack version numbers in their filenames.
-
rEFInd looks for an initial RAM disk in the same directory as the
- kernel file. A matching initial RAM disk has a name that begins with
+
rEFInd looks for an initial RAM disk in the same directory as the kernel
+ file. A matching initial RAM disk has a name that begins with
init and that includes the same version string as the kernel.
- The version string is defined as the part of the filename from the
- first digit to the last digit, inclusive. Note that the version string
- can include non-digits. For instance, the version string for
+ The version string is defined as the part of the filename from the first
+ digit to the last digit, inclusive. Note that the version string can
+ include non-digits. For instance, the version string for
bzImage-3.19.0.efi is 3.19.0, which matches
initramfs-3.19.0.bz; and
vmlinuz-4.2.5-300.fc23.x86_64's version string is
4.2.5-300.fc23.x86_64, which matches
- initrd-4.2.5-300.fc23.x86_64.img. Many other matches are
- possible. If an initial RAM disk is identified, rEFInd passes a
- suitable initrd= option to the kernel when it boots.
+ initrd-4.2.5-300.fc23.x86_64.img. In order to support Arch Linux
+ kernel naming the strings linux and linux-lts are
+ treated as digits. So vmlinuz-linux-lts has version
+ linux-lts, which matches initramfs-linux-lts.img.
+ Many other matches are possible. If an initial RAM disk is identified,
+ rEFInd passes a suitable initrd= option to the kernel when it
+ boots. There are two variants on this rule:
+
+
+
+
As an extension to the preceding point, if multiple initial RAM disk
+ files match one kernel, the one whose filename matches the most
+ characters after the version string is used. For instance, suppose
+ the kernel filename is vmlinuz-4.8.0-32-standard, and two
+ initial RAM disk files are initrd-4.8.0-32-standard and
+ initrd-4.8.0-32-debug. The first of those files has nine
+ matching characters after the version string (-standard),
+ vs. just one matching character (-) for the second. Thus,
+ the first file will be used.
+
+
If the refind_linux.conf file (described next) is present,
+ and if an initrd= specification is present for the option
+ you're using, rEFInd will not add a pointer to the initial
+ RAM disk file that it discovers. This feature enables you to
+ override rEFInd's initial RAM disk discovery. This is most useful in
+ Arch Linux, which can be configured with two different initial RAM
+ disk files, one to be used for normal booting and one for recovery
+ situations. You can specify each initial RAM disk file on its own
+ line, which gives you the ability to control which to use at boot
+ time.
rEFInd looks for a file called refind_linux.conf in the same
- directory as the kernel file. It consists of a series of lines,
- each of which consists of a label followed by a series of kernel
- options. The first line sets default options, and subsequent lines set
- options that are accessible from the main menu tag's submenu screen. If
- you installed rEFInd with the refind-install
- script, that script created a sample refind_linux.conf file,
- customized for your computer, in /boot. This file will work
- without changes on many installations, but you may need to tweak it for
- some.
+ directory as the kernel file. It consists of a series of lines, each of
+ which consists of a label followed by a series of kernel options. The
+ first line sets default options, and subsequent lines set options that
+ are accessible from the main menu tag's submenu screen. If you installed
+ rEFInd with the refind-install script, that script created a
+ sample refind_linux.conf file, customized for your computer, in
+ /boot. This file will work without changes on many
+ installations, but you may need to tweak it for some. If the kernel
+ options string includes the substring %v, rEFInd substitutes
+ the kernel version number for that string. (If you need the actual
+ string %v in your kernel options, use %%v instead;
+ rEFInd will change this to %v.) This feature can be used to
+ match an initial RAM disk file that requires special treatment, such as
+ if you have multiple numbered kernels, each of which has two initial RAM
+ disk files.
If rEFInd can't find a refind_linux.conf file in the directory
that holds the kernel, the program looks for a file called
@@ -408,7 +441,7 @@ extends it as follows:
If rEFInd can't find a refind_linux.conf file or an
/etc/fstab file, it tries to identify the Linux root
- (/ filesystem by looking for a partition with a GUID type code
+ (/) filesystem by looking for a partition with a GUID type code
matching that specified for the root (/) filesystem in the Freedesktop.org
Discoverable Partitions Specification. These type codes are as yet
@@ -469,7 +502,8 @@ total 17943
All the kernels in a given directory use the same
refind_linux.conf file. If you need to set different options
for different kernels, you'll need to place those kernels in different
- directories.
+ directories. (A partial exception is the kernel version string, which
+ can be passed via the %v variable, as noted earlier.)
You must place your kernels in a directory other than the one that
holds the main rEFInd .efi file. This is because rEFInd does
@@ -489,7 +523,7 @@ total 17943
-