Starting with 1.47, changes marked with SYSLINUX/PXELINUX/ISOLINUX apply to that specific program only; other changes apply to both.

• PXELINUX: Allow the DHCP server to override the configuration file name and pathname prefix, using "site-specific" DHCP options.
• PXELINUX: Documentation fixes.
• PXELINUX: Fix the IPAPPEND option; the last two values were reversed vs. what the kernel expected.
• Introduce a way to return to text mode once we are already in graphics mode. This may be useful for F-key help screens.
• Fix several bugs in the way return to text mode was handled.

• ISOLINUX: Support full pathname searches. Max length for a pathname is 255 characters. As a result, only 64 LABEL statements are supported in ISOLINUX.
• PXELINUX: Max filename length extended to 63 characters.

• Add support for graphical splash screens.
• Add mode control characters, which allows you to control message display output depending on output mode (text, graphics, or serial port.)
• ISOLINUX: New program, which boots Linux from a CD-ROM without using floppy emulation mode. See isolinux.doc for more details.
• PXELINUX: Don't search for boot sector file types, since they don't work anyway.
• SYSLINUX: Document the LOCK command for Win9x, and the error dialog box for WinNT/2K.

• PXELINUX: Fix code for finding !PXE from PXENV+. This was due to a spec bug; match the most recent spec since that seems to be what implementations actually do.
• SYSLINUX: Add some smarts to the boot sector, which hopefully should reduce the number of systems which require stupid mode (syslinux -s).
• PXELINUX: Document further some of the pathologies with old PXE stacks.
• When specifying a DEFAULT command line, no longer automatically append auto. See the DEFAULT command in syslinux.doc for more information.
• PXELINUX: Clean up the allocation of local socket numbers.

• PXELINUX: Rename pxelinux.bin to pxelinux.0, to match what most PXE servers seem to expect.
• PXELINUX: Update the DHCP/boot server setup documentation.
• PXELINUX: Support new LOCALBOOT option for LABEL sections.
• PXELINUX: More robust parsing of DHCP/boot server packets.
• PXELINUX: Include a small utility program gethostip to compute hexadecimal IP addresses.

• PXELINUX: Fix bugs introduced by new A20 code. (SYSLINUX has also been changed for code consistency reasons, but I'm pretty sure the changes are don't care on SYSLINUX.)
• Documentation updates.
• PXELINUX: Add IPAPPEND option to generate an ip= option to the kernel.

• PXELINUX: Not all PXE stacks fill in the IP address for a type 3 cached info query. Use a type 2 cached info query for this information (only.)
• Yet another attempt at A20 coding. Now support BIOS call 15:2401 as well, and handle machines which always have A20 on separately.
• Support memory detection using INT 15h, AX=0E820h. BIOS manufacturers have apparently gotten sloppy about keeping INT 15h, AX=0E801h working properly.
• Don't issue onto the serial port when we're doing screen wraparound.

• Yet another A20-code update. It seems some "legacy-free" machines and embedded gear simply don't have a KBC to talk to, and that waiting for one will wait forever. Sigh.

• SYSLINUX: Implement a hack for BIOS drivers which hog significant chunks of low memory during boot. (Note: PXELINUX already had this modification. SYSLINUX does still require that the low 512K is available; PXELINUX requires 384K. Machines with a physical memory hole in the low 640K cannot boot Linux no matter what.) Depending what the reason is for the memory hole, a new kernel (2.4.0-test3-pre3 or later) may be required.
• SYSLINUX: Default installer binary now compiled against glibc 2.1. If this is inappropriate for your system and you still want to use the offical version of SYSLINUX, please follow the instructions in distrib.doc to rebuild the installer.
• SYSLINUX: Linux installer program now supports -o <offset> option which does a loopback mount with the -o loop,offset=<> option. Useful to run SYSLINUX on an individual partition of a whole-harddisk image.
• Include the source code to a Master Boot Record (MBR) functionally equivalent to the one installed DOS except it includes EBIOS support, and should be resistant to geometry changes. The MBR code is public domain.
• PXELINUX: Fix "double p" bug: if the tftp prefix was null, all filenames would get a "p" preprended, e.g. "ppxelinux.cfg" and "pvmlinux".

• PXELINUX: Workaround for PXE ROMs based on the Intel PXE PDK 3.0 build 071 and earlier: missing !PXE structure pointer.
• PXELINUX: Handle larger BOOTP/DHCP packages.
• PXELINUX: The command line passing was broken; fix.
• PXELINUX: Make COMBOOT images work.
• PXELINUX: Documentation on how to make booting work using the PDK 3.0-derived clients, which aren't so generous as to allow booting with only PXEClient specified.

• PXELINUX: RFC 1123 states that a TFTP implementation MUST use adaptive timeout, "at least an exponential backoff of retransmission timeout is necessary." Implement a very simple exponential backoff for retransmits.
• PXELINUX: Updated documentation, including pointer to new TFTP server.
• PXELINUX: When sending ERROR due to bad OACK, use the proper destination port number (why are TFTP port numbers so odd?)
• PXELINUX: If the boot dies in the middle somewhere, eventually give up and reset the machine (unattended operation.)

• New program PXELINUX to do network booting using a PXE-compliant (Pre-Execution Environment) network booting PROM. See pxelinux.doc for details.

• Serial console support. See syslinux.doc for details.

• Change HIGHMEM_MAX to 38000000h to (hopefully) avoid the kernel stepping on it; 3f000000h was apparently a higher limit than the kernel used!

• Add sys2ansi.pl script to display the contents of a colorized SYSLINUX file.
• Changed the io_delay once again, after a report that the old delay port causes hangs on some systems.

• Frob the "fast A20 gate" port as well as the keyboard controller; will this help systems with problems?
• Be even more paranoid about A20, unfortunately even this seems to be not paranoid enough... what I don't understand is that if there is hardware out there this broken, how can it run Linux at all? Report an error message rather than hang forever if A20 is stuck.
• Include some intermediate files in the distribution, plus provide a "make installer" target for distributors to relink the install programs only. I would prefer the syslinux boot loader proper to be "binary clean" for debuggablity -- use "make clean ; make installer" to rebuild the installers only.

• Don't get confused by directories, volume labels, or VFAT long names.
• Use INT 15h, AX=0E801h to query memory size before trying INT 15h, AH=88h. This not only provides more headroom between the kernel and the initrd on large-memory machines, but it appears some recent BIOSes actually have started returning garbage for the AH=88h (older) call.
• Trust high memory beyond the 15 MB mark if the user has specified it, or if obtained with INT 15h, AH=0E801h (with no memory holes above 1 MB.)

• Increase A20M delay and put in a test to avoid problems on certain IBM Thinkpads (thanks to Donnie Barnes of RedHat for vital info on this one.)
• Support COMBOOT style boot command images.
• Support chain loading (foreign operating systems, e.g. DOS).
• Include a new copybs DOS utility to copy a boot sector to a file (under Linux, use dd.)
• Fix the DOS installer to work for disks over 32 MB.
• SYSLINUX should now handle disks with more than 65536 tracks.

• Fix a bug that caused LABEL statements in syslinux.cfg to not be handled properly.
• Updated the documentation. Among other things, we now allow up to 128 "label" statements.

• Fix for booting old (pre-initrd) kernels.
• It seems at least some versions of OS/2 doesn't set up all the fields in the superblock correctly. Account for that.
• Fix bug that caused boot failure when using the mem= option.

• Loading from partitions now should work properly. (Actually tested, this time. You should even be able to dd a floppy to a partition and boot from it.)
• Removed large workaround code for an alleged ancient BIOS bug I have never actually seen. The -s option should work on those machines, anyway.
• Support for simple keyboard remappings, same as used by LILO (once again to support localization.) The program keytab-lilo.pl from the LILO distribution included to generate such maps.
• Added a "safe, slow and stupid" (-s) option to the installers. This option will lobotomize the boot sector to hopefully work on even very buggy BIOSes.

• Ability to load a VGA font on bootup (for localized Linux distributions.)

• Bug fix in the Linux installer.
• Added a workaround for a bug in certain AMI/Intel BIOSes when booting from CD-ROM.
• Documentation changes.

• FAT16 filesystems are now supported.

• Now compiles under Linux, using NASM, rather than using Turbo Assembler under DOS. See http://www.cryogen.com/Nasm for information about NASM.
• Linux-hosted SYSLINUX installer, as well as a rewritten DOS installer (now is written in assembler, so we don't need Turbo C.)

• Added support for loading bzImage and initrd loading, and made SYSLINUX new-setup-code aware (SYSLINUX 1.30 id=0x31).
• Added LILO-style kernel labels; see the LABEL and IMPLICIT keywords in README file.
• Added support for colorization of intro and help screens.
• The vga= option is now handled correctly.
• Massive rewrite of large chunks of the code in order to support the first two new features.

• Added simple online help at the boot: prompt.
• Removed 2880K image as I no longer have access to such a floppy drive. (Donations accepted!!)
• Decided to distribute the source in a subdirectory rather than in a nested zipfile.

• Removed a sanity check which would cause booting to fail on Phoenix BIOS version 4.03. Apparently this BIOS is buggy.

• Added configuration file SYSLINUX.CFG. This file contains all configurable options, and can be edited from any OS which can access an MS-DOS filesystem; there is no longer a need to run SYSLINUX.EXE except to write the boot sector.
• Default command line now given by DEFAULT line in config file.
• LINUXMSG.TXT and BOOTMSG.TXT hard-coded file names replaced by DISPLAY and PROMPT lines in config file.
• LILO-style option appending now supported (APPEND line in config file).
• Prompt timeout is now supported (TIMEOUT line in config file). The timeout is cancelled when anything is typed on the command line.
• Pressing <ESC> or <Ctrl-C> at the Loading... stage now aborts the kernel loading in progress and returns the user to the boot: prompt.
• The installer now automatically sets the READONLY flag on LDLINUX.SYS.
• Added 2880K disk image.

• Fixed bug that would prevent booting from double-density floppies and other DOS filesystems with multiple sectors per cluster.
• Added 720K disk image.
• Changed default kernel name on disk images to LINUX.

• Fixed bug that would garble the command line on recent kernels with more than 4 sectors of setup code (this wasn't really a bug; rather, a kernel change broke the code. Unfortunately the Linux boot interface is still sorely undocumented).
• Added BOOTMSG.TXT file support (message file which does not force display of the boot prompt).

• Fixed bug on some (most?) 386 BIOSes would require two boot attempts.