Originally written: 3/14/2012; last Web page update:
-7/6/2014, referencing rEFInd 0.8.3
+3/4/2016, referencing rEFInd 0.10.5
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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.
+
As described in reference to version 0.9.2 on the Revisions page, rEFInd includes a
+ delicate and hackish workaround to a problem introduced by Shim
+ 0.8. Developing a better solution to that problem is a high
+ priority.
-
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.
+
rEFInd's Makefiles and, to a lesser extent, C code,
+ support x86, x86-64, and ARM64 CPUs. EFI is also
+ available for Itanium (IA-64) and ARM32 CPUs, so I'd like to add
+ this support.
+
+
Currently, rEFInd can detect whether it's compiled for x86,
+ x86-64, or ARM64 systems and displays this information in
+ its "About" screen (AboutrEFInd() in main.c). I'd
+ like to add detection for Itanium and 32-bit ARM systems, but I
+ have no way to test such changes.
Further to the preceding, rEFInd's GPT-scanning code (used to
extract partition names) includes assumptions about byte order, and
@@ -203,7 +202,31 @@ href="mailto:rodsmith@rodsbooks.com">rodsmith@rodsbooks.com
upper-left corner of the screen. Having an option to support a
transparent background is desirable to some users.
-
+
When delivering rEFInd as a boot loader from a network server,
+ rEFInd is limited to its default options and can boot only local
+ OSes, not network OSes. The cause is that the server delivers a
+ single file, so rEFInd is divorced from its configuration and
+ support files.
+
+
A way to identify specific Windows versions and present unique
+ icons or change the text is desirable. Currently, a crude
+ distinction of XP and earlier vs. Vista and later is possible for
+ BIOS-booting on Macs, but no such distinction is made for EFI-mode
+ booting, and nothing finer-grained is attempted. Improvements will
+ probably require identifying unique features of each version's boot
+ loader files or boot sector code.
+
+
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.
+ This said, BIOS support is becoming increasingly unimportant as the
+ transition from BIOS to EFI continues, so I'm unlikely to put effort
+ into this issue myself.
+
+
Known bugs that need squashing:
@@ -217,8 +240,25 @@ href="mailto:rodsmith@rodsbooks.com">rodsmith@rodsbooks.com
removing rEFInd's drivers has caused the problem to go into
remission.
Another Mac-specific display problem relates to "retina" displays:
+ Some users report that rEFInd comes up in a lower resolution than
+ the screen supports, and that this setting persists into the running
+ OS X instance, and can't be adjusted using the usual OS X means.
+ Unfortunately, I lack the hardware necessary to experiment and find
+ a solution to this problem within rEFInd. Thus, a fix will have to
+ wait for me to get my hands on such hardware (which is not on my
+ immediate purchase list) or until somebody with such hardware and
+ the necessary skills submits a fix. (Note that a fix could
+ conceivably involve passing options to the OS X boot loader or
+ something else that would require trivial or no changes to rEFInd.)
+ I've heard that this problem affects not just rEFInd, but also GRUB,
+ and even Windows when dual-booting on a Mac; see this YouTube video
+ and This
+ AskUbuntu question and answers, for instance.
+
+
Some EFIs have bugs that cause 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
@@ -226,14 +266,10 @@ href="mailto:rodsmith@rodsbooks.com">rodsmith@rodsbooks.com
"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.
+ mismatch if the path includes lowercase elements). This problem is
+ worse when compiling rEFInd with GNU-EFI than with Tianocore.
+ Version 0.9.1 has made improvements on this score, but some issues
+ may continue to lurk.
The Shutdown option works correctly on Macs, but not on many UEFI-based
PCs. On such systems, Shutdown reboots the computer. This should be
@@ -254,6 +290,13 @@ href="mailto:rodsmith@rodsbooks.com">rodsmith@rodsbooks.com
have the equipment and skill to do so, I'd be interested in
receiving a patch.
+
If you use a true MBR disk on a Mac to boot Windows or some other
+ BIOS-only OS, and if that disk has an extended partition, bogus
+ additional BIOS/legacy-bootable options may appear in the rEFInd
+ menu. The reason appears to be a bug in the handling of
+ extended/logical partitions in the refind/lib.c file, but
+ I haven't fully tracked it down.
+
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.
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.
+
Currently, debugging rEFInd requires adding Print()
+ statements to the code. Adding a logging facility that supports
+ multiple log levels and writes the output to a file would help with
+ debugging, especially when dealing with problem reports from
+ users.
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.
@@ -333,6 +366,15 @@ href="mailto:rodsmith@rodsbooks.com">rodsmith@rodsbooks.com
detected boot programs and create a set of manual boot stanzas for
them, so that they can be modified manually.
+
Better support for touchscreens and/or configurable buttons for
+ rEFInd's actions would enable use of rEFInd on tablet computers that
+ lack complete keyboards. (Version 0.10.4 supports some
+ touchscreens, but this feature relies on support in the firmware,
+ which is not universally present.)
+
+
The ability to rotate the display for users who rotate their
+ monitors or who use tablets would be helpful.
+
GRUB provides a configuration-file command called outb
that enables manipulating hardware registers. Something similar,
via the mm command, can be done in the EFI shell. I'd like
@@ -357,13 +399,19 @@ href="mailto:rodsmith@rodsbooks.com">rodsmith@rodsbooks.com
loader settings—say, to disable one specific boot loader or
change its icon.
-
The ability to rotate the display for users who rotate their
- monitors would be helpful.
+
A GUI configuration tool for host OSes (Linux, OS X, Windows, etc.)
+ 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.
+
+
The ability to produce audio output (at least a simple "beep") to signal
+ to visually impaired users when rEFInd is ready to accept input would be
+ helpful.
-
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.
+
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.
Improvements to gptsync, refind-install, or other
support tools:
@@ -401,13 +449,10 @@ href="mailto:rodsmith@rodsbooks.com">rodsmith@rodsbooks.com
under some circumstances, such as when it makes no changes to the
partition table. Fix this.
-
When updating a system with Secure Boot via an RPM or Debian
- package, the RPM installation script can detect rEFInd's existing
- shim or PreLoader program and pass options to install.sh
- to try to copy these programs over themselves. This results in a
- message that the copy was over the same file and an error message
- that there were problems with the installation, although this isn't
- really the case.
+
rEFInd's support for network booting is primitive and relies on the
+ external iPXE package. In my own testing, iPXE retrieves the
+ BIOS-mode boot loader from some servers that offer both, which
+ makes it useless on those networks.