The rEFInd Boot Manager:
The Future of rEFInd
by Roderick W. Smith, rodsmith@rodsbooks.com
Originally written: 3/14/2012; last Web page update:
1/8/2013, referencing rEFInd 0.6.4
I'm a technical writer and consultant specializing in Linux technologies. This Web page is provided free of charge and with no annoying outside ads; however, I did take time to prepare it, and Web hosting does cost money. If you find this Web page useful, please consider making a small donation to help keep this site up and running. Thanks!
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This page is part of the documentation for the rEFInd boot manager. If a Web search has brought you here, you may want to start at the main page.
rEFInd is far from perfect. It's based on rEFIt, which has a list of active bugs on its project page on Sourceforge. I have not studied this bug list in detail for rEFInd's first release, although I've probably fixed a few of those bugs because I encountered them myself. Other bugs I may never fix because I lack the necessary hardware for testing.
This page exists to document some of rEFInd's known bugs and limitations, as well as features I hope to add in the future. Some of the items on this list are things that you may be able to help with, so if you'd like to contribute, feel free to drop me a line!
The following list groups things that need to be done into broad categories. In some cases, there's some ambiguity about how an item might best be classified. Without further ado, then:
- Tasks with which non-programmers can help:
- Testing! rEFIt was complex enough that changes such as the ones
I've made have the potential to disrupt the program's operation in
unexpected ways. Since the initial 0.2.0 release, I've continued to
add features to rEFInd, and every new feature is another way for
bugs to get into the program. I can only test on a handful of
systems with a limited number of configurations. Therefore, if you
try rEFInd and run into bugs, please report them to me!
- I have little talent with graphics manipulation programs, so
rEFInd's boot logo, such as it is, is pretty weak. If you have
artistic talent and would like to create a rEFInd logo, please feel
free to send it to me. I won't make any final decision about
changes until at least June 30 of 2012.
- rEFIt's original design, and hence rEFInd's design, enables easy
theming by replacing icon files. If you'd like to design a new
theme for rEFInd, feel free to submit it. I might or might not
replace the icons it uses now (most of which come from the Oxygen
Icons package), but I may provide links to themes on this Web site
(or even host them on the project's Sourceforge page). For more
information on designing themes for rEFInd, see the Theming rEFInd page.
- Improvements to existing features:
- The support for booting legacy (BIOS) OSes on UEFI-based PCs
currently has a number of limitations. Most importantly, it works
off of the list of boot devices stored in the computer's NVRAM. I'd
prefer to have it scan disks and partitions, as the Mac's legacy
boot support does. Also, the UEFI legacy boot code presents empty
optical drives and uses generic icons rather than OS-specific
icons.
- Currently, rEFInd can detect whether it's compiled for x86
or x86-64 systems and displays this information in its
"About" screen (AboutrEFInd() in main.c). I'd
like to add detection for Itanium and ARM systems, but I have no
way to test such changes.
- The code could be more flexible in its handling of the sizes of
various graphical elements, and particularly drawn text. Prior to
version 0.2.2, submenu text was invisible on UEFI-based PCs with
800x600 and smaller displays because of an inability to properly
crop the graphics fields that hold the text. With version 0.2.2,
I've put a band-aid on this problem by reducing the field size so
that it now works on 800x600 displays, but smaller displays still
suffer from this problem. This is just an example of the
inflexibility of certain layout issues within rEFInd.
- Although the ICNS file format used by rEFInd supports multiple
image sizes, if a size that rEFInd needs isn't present in the file,
rEFInd can't use the icon. The ability to scale images to the
desired size would be useful.
- I would like to be able to specify the volume on which a boot
loader resides using a partition GUID value, but extracting a GUID
from the partition data is harder than extracting the volume's
label or counting up the filesystem numbers.
- Currently, if a filesystem's label comes up empty, rEFInd
substitutes the size, so you get displays like boot
EFI\foo\bar.efi from 90 GiB volume. I'd like to add more
checks to substitute the GPT partition label if the
filesystem label comes up empty, or add a filesystem type
identifier to the size.
- The default_selection option in refind.conf could be improved by
supporting a list of default options, so that if the first item
isn't found, rEFInd will try to boot the second one in the list,
and so on. This could be handy in case a driver fails to load, or
to provide an override in case the user inserts a specific
removable disk—by placing the removable disk's name first in
the list, it will take precedence over the normal hard disk
default.
- Along the lines of the previous item, the default_selection might
be expanded to support some form of specification of disk types, as
in a special entry for any optical disk or any external disk, no
matter what its name is.
- It would be useful to be able to specify paths to boot loaders
and/or initial RAM disks relative to the rEFInd directory (or the
boot loader's directory, in the case of initrds).
- Known bugs that need squashing:
- The Gigabyte
Hybrid EFI has a bug that causes the allegedly case-insensitive
StriCmp() function to perform a case-sensitive comparison.
This causes any number of bugs in file matching. For instance:
Changing the case of icon filename extensions (or various other
parts of icon filenames) causes icons to be replaced by ugly
"generic" ones; and rEFInd sometimes appears in its own menu (the
firmware sometimes returns an all-caps version of the filename, but
other times returns the filename with the correct case, causing a
mismatch if the path includes lowercase elements). Some of these
problems can be overcome by converting both strings to be compared
to one case before doing the comparison, but others aren't so easy,
since I think StriCmp() is being called internally to the
EFI. In any event, it'd be nice to fix some of these problems.
OTOH, this is a workaround for a bug on just one EFI
implementation, and a dismal one at that, so I'm inclined to just
let it go.
- The Shutdown option works correctly on Macs, but not on many UEFI-based
PCs. On such systems, Shutdown reboots the computer. This should be
fixed.
- The media-ejection feature (F12) should be extended to work on
UEFI-based PCs and early Macs. At the moment, it relies on an
Apple-specific EFI extension, and I know of no standard EFI way to
do it.
- The re-scan feature occasionally produces odd results, such as
ignoring new media or keeping old media that have been ejected.
This should be investigated and fixed.
- The "scanning for new boot loaders" message that appears during the
re-scan feature is primitive. Some sort of dynamic icon would be
nice, but perhaps impractical, given the single-tasking nature of
EFI.
- On my Mac Mini, launching a shell, returning, and performing a
re-scan causes the system to be unable to launch the shell again. I
have not observed this behavior on UEFI-based PCs. It seems to be
caused by a truncated DevicePath to the shell, which includes the
shell's pathname but not the device identifier.
- When specifying a volume by name in dont_scan_dirs,
slashes are converted to backslashes in the specification but not
in the actual volume name read from disk. Thus, you can't specify a
volume by name if it includes a slash (as in Fedora
/boot). Workarounds are to rename the volume to omit the slash
and to use a filesystem number rather than a volume label.
- The code is in need of review to search for memory leaks and
similar problems.
- New features I'd like to add:
- EFI supports network boots. rEFInd doesn't, but it would be nice if
it would.
- There's currently no way to create a manual boot stanza for a
BIOS-booted OS. This isn't a big priority for me personally, but I
can see how it could be for some people.
- I've received queries about rEFInd's ability to work with Apple's
whole-disk encryption scheme that's new with OS X 10.7.
Unfortunately, I lack the hardware to test this, but my
understanding is that it will work correctly if rEFInd is
installed in the ESP rather than on the Mac OS X root partition.
See this
forum thread for more information.
- I'd like to find a way to enable users to enter customizations for
boot options and then save them to the refind.conf file.
One possible way to implement this would be to have manual boot
stanzas override auto-detected boot loader definitions for the same
boot loader file.
- I have thoughts about creating an EFI configuration tool and
information utility—something to tell you about your hard
disks, enable you to manage MOKs, adjust boot loader priority in
the NVRAM, and so on. This would be useful in system maintenance
and in recovering from boot problems.
- An installation tool for the EFI environment would be useful.
A simple EFI shell script might work, but because this function
requires access to the bcfg command, this would work
only from a version 2 shell or if bcfg were implemented
as a standalone program. Another alternative would be a program
written in C.
- It should be possible to override specific auto-detected boot
loader settings—say, to disable one specific boot loader or
change its icon.
- A way to set the color of the font would be useful for theming
purposes.
- Going further, the ability to load arbitrary other fonts, ideally
in a standard format, would be desirable for theming purposes.
- A GUI configuration tool would be nice, but it's low on my personal
priority list. If you'd like to contribute, I prefer something
written in a cross-platform GUI toolkit, so that a single code base
can be used on any of the major OSes.
- Improvements to the EFI drivers:
- Drivers for additional filesystems are desirable. Given the talk of
shifting to Btrfs, that should be the priority; however, other
Linux filesystems, UDF, and perhaps others would all be welcome
additions. Also along these lines, adding drivers for Linux LVM and
RAID setups would be useful, too.
- As detailed on the drivers page, there
are performance issues with the drivers on some systems. I suspect
that most "real" computers aren't greatly affected (in my tests,
the problem is worst with VirtualBox, and the next worst is a
system that uses DUET). Nonetheless,
I'd like to track down the cause and fix it.
- The HFS+ driver returns a volume label of "HFS+ volume", no matter
what the volume's real label is.
- This may not be possible, or it may require a new driver, but a way
to have the drivers access files (like a Linux loopback mount) is
desirable.
- When built with the GNU-EFI package, an attempt to load more than
one driver on my 32-bit Mac Mini causes the computer to hang. I do
not have this problem with 64-bit drivers on my UEFI-based
computers. I don't know if this is a 32-bit issue or a Mac issue.
This is not relevant if you're using my binary package,
since I build it with the TianoCore EDK2, and the drivers built in
that way don't exhibit this bug.
copyright © 2012–2013 by Roderick W. Smith
This document is licensed under the terms of the GNU Free Documentation License (FDL), version 1.3.
If you have problems with or comments about this Web page, please e-mail me at rodsmith@rodsbooks.com. Thanks.
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