Accessories
Here are some accessories I’m considering buying to improve
my C64 experience. Prices are current as of April 2026.
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ROM replacements
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* JiffyDOS[1] (kernal and disk drive ROM replacement) $20
* One ROM[2] (software-defined ROM) $20–$30
* EasyFlash 3 cartridge[3] $65
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Disk drive replacements
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* SD2IEC[4] (SD card reader) ~$30 (also ebay and other
places)
* uIEC/SD[5] (variant of SD2IEC) ~60
* Pi1541 (1541 emulator) ~$30 (ebay)
* Meatloaf[6] (networked disk drive emulator, SD card
drive, etc.) $60
* Ultimate-II+L cartridge[7] (dual 1541/1571/1581 drive
emulation via USB drives, Commodore 1750/1764 REU, RTC,
CD/DVD via USB, ethernet, dual SID, cartridge emulation,
freezer, tape emulation, ...) 148 EUR
The latter two are far more than disk drive replacements.
The Ultimate-II+L is the whole kitchen sink!
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Network interfaces
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* 64NIC+[8] (network interface) $54
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Mouse adapters
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* PS/2 mouse to 1351 convertor[9] (also here[10] and
here[11]) $23
* Micromys V5[12] (PS/2 mouse to 1351 convertor with middle
button and scroll wheel support) 38 EUR
* MouseSTer[13] (USB mouse to 1351 convertor) £44
* USB adapter for mice/joysticks[14] $20
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Miscellaneous
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* New PSU (or a 9VAC/1A adapter and a 5VDC/1.5A adapter
spliced together to a DIN 45329 connector)
* XoomFloppy[15] (IEC to USB adapter) $37
The XoomFloppy can be used to connect a Commodore floppy
disk drive to a modern computer (useful for archiving your
old disks or writing files/disk images to floppy disks to be
used on your C64).
Many people will tell you to replace or repair your old
Commodore 64 PSU and for good reason: when it fails it can
fry your computer! The 5V DC output increases with age
and/or usage. Once it reaches about 6V, Bad Things can
happen—your RAM is killed, your SID chip dies, your VIC-II
chip goes up in smoke, etc.
A new PSU is cheaper than repairing your C64, so don’t risk
it. That’s not to say that I haven’t risked it in the past,
but I recently removed the potted innards from mine and am
planning to rebuild it with all new parts. All you need is
a 5V/1.5A regulator and a 9V/1A AC transformer. In some
cases you can skip the transformer—it’s used only for the
time-of-day clock and a cassette drive (and some user port
devices use it). If you don’t need any of those then it’s
optional.
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Notes
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The Ultimate-II+L cartridge essentially obsoletes the
Pi1541, SD2IEC, and the XoomFloppy (since files or whole
disk images can be copied from a floppy disk to a USB flash
drive). It also may fill the role of a network interface
like the 64NIC+ (though networking has about 42 million
different ways on the C64 since there’s no common API).
Many devices use the user port or the datassette port for
power. The Ultimate-II+L is a cartridge so uses power from
the expansion port. I don’t particularly care about the
datassette port anyway, so that doesn’t really matter either
way to me. I have only a small handful of cassette tapes
for my C64, and I can easily archive those to my computer
with any tape player with a headphone or line out connector.
I also wrote some software many years ago to convert an
audio file to a TAP file and to extract programs from a
TAP file; I can’t exactly remember since it’s been around
15 to 20 years since I wrote it, but I might have also
written software to convert a TAP file back to an audio
file that can be recorded to tape if needed. Then again,
the Ultimate-II+L does support or emulate a tape drive in
various ways (a datassette adapter and cable are available
from the same shop).
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This all might look like an advertisement for the
Ultimate-II+L, but it’s not. I am just really
impressed by its capabilities, and I’ll probably buy
one for myself in the not-too-distant future.
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So for my purposes I’m thinking of narrowing down the
accessories to:
* A new PSU
* Ultimate-II+L
* A mouse adapter (I’m still looking at features of the
various options)
I might also splurge on JiffyDOS, though I’m also looking
at the open-source MEGA65 Open ROMs project[16] which
supports the JiffyDOS fast loader protocol. And of course
Ultimate-II+L can use alternate ROMs for the kernal and the
emulated 1541 drive, so it seems I could load the JiffyDOS
ROMs on both.
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References
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[1] https://store.go4retro.com/jiffydos-kernal-rom-overlay-ic/
[2] https://onerom.org/buy/
[3] https://store.go4retro.com/easyflash-3/
[4] https://www.tfw8b.com/product/internal-fit-sd2iec-classic-v1-1/
[5] https://store.go4retro.com/commodore/uiec-sd/
[6] https://www.tindie.com/products/masteries/meatloaf-fujinet-commodore-64-wifi-sd-interface/
[7] https://ultimate64.com/U2PLBLK
[8] https://store.go4retro.com/64nic/
[9] https://www.ebay.com/itm/287082419275
[10] https://www.anyretro.com/products/commodore-64/1351-compatible-optical-mouse/
[11] https://www.norhampton.com/product-p-459489.html
[12] https://www.protovision.games/shop/product_info.php?products_id=358&language=en
[13] https://retrolemon.co.uk/atari-st-ste-falcon/133-mouster.html
[14] https://github.com/emanuelelaface/USBtoC64/
[15] https://www.ebay.com/itm/255446346569
[16] https://github.com/MEGA65/open-roms/