The 1541/1571 Alignment system is probably the most well known alignment software. Not only will this software tell you if you drive is aligned, it also gives instructions on how to fix your alignment. This program requires a calibrated disk.

1541 / 1574 Drive Alignment Users Manual by Free Spirit

If you like to make lists for chores, grocery shopping, bills to pay, etc.... this is the program for you. Full printer support.

This handy alignment utility is a little different than the others I've seen because it lets you manually move the head between track 1 & 35 while checking alignment results.

1541 Allignment (programmers spelling, not mine) by ANTIRAM in 1984.  If you don't know what this is for you probably don't want it.

Written by Greg Granville - 1541 Alignment Check is one of the few (if not only) drive checker that is run with a joystick. Kinda curious why someone would create a utility like this with joystick control.

1541 Alps Drive Check goes beyond the usual alignment check and speed test, it also checks the drive LED, stepper motor, Stop limits, disk read/write and write protect. Also works on devices other just 8.

1541 Disk Drive Alignment [CSM] Manual

1541 Disk Drive Alignment V2 [CSM] Manual

Written by Christopher C. Capon. Officially this program is called the Sing Song Serenade for the c64 and 1541 / 2031. Anyway, its a really cool program that makes your floppy drive play music by what I assume is vibrating the heads. If you've never tried it on a real 1541 you have to do it at least once.

Besides the usual head alignment test, this program will also test disk rotation speed.

1541 File Unscratcher is a simple utility to recover a deleted file.  This program is from the appendix of the 1541 users guide.

1541 floppy drive rendering.  Download for full size image.

The 1541 Maintenance Guide is produced to give a brief, concise source of pertinent information necessary for maintenance of theVIC-1541 and the 1541 disk drives. Most of the information in this Guide has come from the 1541 Maintenance Manual, which isalso published by Peltier Industries. For those persons desiring more thorough coverage of the 1541 series of disk drives, the 1541 Maintenance Manual is available through authorized dealers.

1541 Physical Exam Users Manual

Sometimes you just want to know that the disk you're going to use is in good condition and your disk drive gets along nicely with it.  Here's a simple but effective tool for testing that disk.  1541 Sector Tester will read every track and sector on the disk and let you know if an error is returned.

1541 Speed Test by Zibri - Need to diagnose an issue with your sick, well here's a tool that can help.  Although it seems straight forward, I highly recommend reading the documentation, especially if you don't want to bork the disk your testing with.

It's really nice when people put out quality software and share it with the world.  1541 Speed Tester is just such a program, and it deserves some more attention.  Please visit the software project page at https://github.com/Zibri/C64-1541-Speed-Test.  I also recommend visiting the authors web page at https://www.valoroso.it/regolare-il-commodore-1541-con-speed-test-by-zibri/

Written by a Late Night Hacker on November 10th, 1984. Can't really say much about this copier other than it's probably super kwik!

This is a newer test demo disk that comes with the Commodore 1541 floppy drive.  It includes demo programs for the Commodore 16,64 and Plus4.

1541 Test Suite by Wolfram Sang, released in 2008.  This is a 3 disk collection of extensive testing for the Commodore 1541 and compatible floppy drives.  Documentation and explanation of the tests is included in the archive.  The official source for this program is here.

This is the Commodore 1541 test / demo disk that comes with a new 1541 floppy drive.  This is the earliest version, from December 1984.

1541-Format to 1571-Format Convert v1.3 by Shadowsoft (02/21/89) is a Commodore 128, 80 column mode program that will chage the format of a 1541 floppy to 1571 without destroying the data on the 1541 side.

Added features since 1.24

• Debug stream over Ethernet, which logs CPU / VIC access real time, also possible to log C64 CPU and 1541 CPU alongside. U64 only.
• ACIA (MOS 6551) emulation
• Modem Layer emulation (6551 <-> LAN), supporting both outbound and inbound connections
• REU load / save commands from UCI, using the preload settings
• File append mode for Software IEC.
• Support for SuperGames cartridge

This 60 page doc covers all three of the 1541 Ultimate units (1541u, 1541u II, 1541u II+).

1541 Ultimate Firmware v1.5:

- Show all entries in a D64 when loading directory through software IEC- Show all entries in a D64 when loading directory through software IEC

Known issues:

- CD:/ of the software IEC mode is broken- MOUNT: is partly broken (1541-bug-workaround was removed because we forgot why wedid that! Temporary solution: Issue initialize command to 1541 after mounting a D64: @8, @I)

Fixed from 1.5beta

- The menu waits until you release the keyboard before exiting.

1541 Ultimate Firmware v1.6

- Reads from the Ethernet chip have been fixed. The unit now correctly receives packets.

1541 Ultimate V1.7 beta Firmware Download

Installation instructions: 

1) Make sure that in your current configuration, the "application to boot" is set to "appl.bin" (the default).

2) Unzip the zip file into the ROOT of an SD-card, of which you have made sure that the 1541 Ultimate can read it.

3) Place the SD-card in the 1541U, and make sure the 1541U is correctly inserted in a C64/C128 expansion slot.

4) Turn on the C-64 and watch the screen output.

5) Turn off the C-64 when the update is finished.

In comparison to 1.6, the following has been changed:

• The freezer has been made more robust. (Needs more testing)
• Minor fixes in the IEC interface (but not yet satisfactory)
• SID player has been added
• Epyx Fastloader cartridge has been added
• Support for custom carts has been added (8K/16K, as well as existing carts)
• Support for (custom) Ocean and System3 cartridges added.

This is a BETA release.

1541 Ultimate Firmware 1.72b [unofficial] with WVLs config save flash indication and P00 support, patched with the Ultimate-freezercode from 2.0 firmware (demos like Another Beginning and We Are New now works) and added the (Blu)REU-imagesupport. by Tommi Lempinen

As far as I can tell, this is the latest and last firmware update for the original 1541 Ultimate as of August 2019.  This firmware was released in 2012.

1541 Ultimate Firmware v2.5 [unofficial] with KCS power cartridge support, 1 drive and sound

Released in November 2013, this firmware for the 1541 Ultimate I is the latest unofficial firmware available.  More information on this firmware by Obliterator918 can be found here.

The ‘Ultimate Audio’ feature is a new feature for the 1541 Ultimate-II module. It implements multichannel audio sample playback support from REU memory, and is an exciting addition to the possibilities this cartridge offers. 

1541 Ultimate II Firmware 2.5a

1541 Ultimate II Firmware v2.4a

1541 Ultimate II Firmware v2.4c

Version 2.5 includes some new features:

• File viewer.
• Selectable colors in user interface.

This version also includes some fixes for nasty memory allocation bugs that existed when using USB sticks. Removal of a USB device is now at least a lot safer. Also, some file system bugs were fixed.

Version 2.5+ includes some new features:

The ‘plus’ version of 2.5 including a special 7-voice audio engine. This version is based on the same 2.5 with the bugfixes and a special FPGA build can it only supports ONE floppy drive, in favor of extra audio functionality.

1541 Ultimate II-Firmware v2.5x

Version 2.6 includes some new features:

• Disk Copier from real drives to .D64 images
• Command Interface
• Ultimate-II DOS V1.0 (command target)
• Kernal replacement function

... and some important fixes, including:

• TAP file recorder failed miserably on high latency write devices. Rewritten; should work better now.
• Drive data timing has improved. Timing is now dependent on the data track itself, not on the speed setting of the VIA. This fixes some protected titles in G64 format.

Release notes:

• This version does *not* include SID, but it does include the Ultimate Audio module. Different builds may become available upon request.
• The internal copier is still in beta. It has been tested with some of my drives, but there might be drives out there that won't work. Make sure you have an IEC link from the Ultimate to a real drive to use this function. (No need to have a link to the computer.) There is still no retry mechanism; sectors that failed to read correctly will not be re-read.
• The Kernal replacement function is critical when it comes to timing. Tested on two machines only. Might not work on C128.

Installation instructions:

• Unzip the downloaded file into the root of your SD card.
• Place the SD card in the 1541Ultimate II.
• Boot your Commodore machine
• Wait for instructions and remove SD after flashing. Suggestion: remove 'update.bin' from the root of the SD, using the PC or the delete command in the Ultimate.

Command Interface and Ultimate-II DOS

See the documentation of the Command Interface module for knowing how to use it!

See the documentation of the Ultimate-II DOS, to get to know what you can do with the Command Interface in this firmware release.

Release notes 2.6d:

• * Ultimax mode forced now correctly implemented (solves issue with freeze and DMA load)
  * Programmable cartrige emulation timing
  * Some drive emulation enhancements
• FIXED: Ultimax mode forced now correctly implemented (solves issue with freeze and DMA load)
• FIXED: Updater now works on C128... (not all C128 issues are fixed)
• ADDED: Programmable cartrige emulation timing
• IMPROVED: Some drive emulation enhancements
• Release notes 2.6c:

• This version does include SID, but is just single-drive. It does include the Ultimate Audio module. Different builds may become available upon request.
• FIXED: USB stick present on boot time caused the Ultimate-II to crash when loading a file from SD at initialisation time (kernal rom / drive rom)
• FIXED: Starting a program with RUN sometimes caused the ultimate to become unresponsive when freezing afterwards.
• FIXED: Now reads USB sticks with FAT16 format, but without partition table.

See for additional information the download item of V2.6

1541 Ultimate II Firmware v2.6e Dual Drive [unofficial]

1541 Ultimate II Firmware v2.6g

1541 Ultimate II Firmware v2.6g w/1 drive and SID [unofficial]

Version 2.6h contains some small fixes on top of 2.6d.  This build is a DUAL DRIVE version with NO SID emulation.

• Release notes 2.6h
• Timing fixed for C64C
• Newer version of built-in MOD player
• Bug fixes regarding USB stick removal
• Enhancements under the hood for networking support. Network support will be enabled later, is not part of this version!

See for additional information the download item of V2.6d.

1541 Ultimate II Firmware v2.6k w/audio

1541 Ultimate II Firmware v2.6k w/dual drive

1541 Ultimate II Firmware v3.0 Beta 4

A new version of the firmware for the interface 1541 Ultimate II is released. This version runs only on the 1541 Ultimate II cartridge (new fpga).

Release notes 3.0 beta 5:

Major:

• BUGFIX: Processor’s Data Cache stored result of IO read, causing wrong values to be read from the cache

Minor:

• C64 Keyboard scan made a bit slower  (not tested)
• Fixed configuration drop down
• Fixed clock settings
• Mount disk made first option in D64 file type
• Updated Final 3 cart.

Release notes 3.0 beta 4 (first version released on Facebook):

• The FPGA platform has gotten an upgrade. There is now a faster RISC processor on board (~10 times faster), and I have re-written the USB host controller, which has become ~50 times faster. The external memory of the FPGA also runs faster, and delivers now also approx. 7 times more bandwidth. With this faster platform, it has become possible to run a multithreaded OS.
• There is now support for USB2LAN adapters, and 3.0beta4 runs two services: a (raw-)telnet (VT100) server that brings up the menu, and an FTP daemon for basic file transfer.
• There is now support for reading the directories of D71 and D81 files in the browser.
• There is a ‘CD’ command in the software IEC, and other improvements have been made to the soft IEC driver.
• There is now a copy command in the file browser, that works with C=C/C=V (or CTRL-C / CTRL-V). It is not that fast, but for small files it works. You can also copy files from inside a D64/T64 to another location in the file system. The other way around is still under development, but will soon be possible as well.
• UltiCopy is disabled for now, because it still needs to be ported to the multi-threaded operating system.

3.0 BETA 7
=========

r297 | gideonz | 2016-04-15 21:27:25 +0200 (Fri, 15 Apr 2016)

** Contains firmware for both 1541 Ultimate II and 1541 Ultimate II+

 Release notes 3.2

3.2
===

• Completely rewritten SID player, by Wilfred Bos
• Enhanced version of FC3, by Daniël Mantione
• Added Tape Index function, as suggested by Tom Roger Skauen
• Added UCI interface to access the network (TCP/IP and UDP/IP) through Ultimate Command Interface  (documentation pending)
• Many additions and bug fixes by Henning and Markus, including Home Directory, REU load on startup, EasyFlash write support (manual save), and more.
• Some enhancements in FTP server
• Additional bug-fixes.

Installation instructions:

• Copy unzipped file to USB stick.
• Put the USB stick in the U2+.
• For the 1541 Ultimate-II:
  • Navigate to the unzipped file 'update_audio_3.2.u2u' or 'update_dual_drive_3.2.u2u' and select "Run Update"
• For the Ultimate-II+:
  • Navigate to the update_3.2.u2p file, and select "Run Update".