Pi1541 and fast load cartridges

Last Updated on December 8, 2020 by Dave Farquhar

This spring I bought myself a couple of things: a Raspberry Pi, so I could build a Pi1541, and an Epyx Fast Load cartridge. I didn’t have a Pi1541 as a kid of course, and I didn’t have a fast load cartridge either, but I wanted to speed up my new Pi1541. Imagine my disappointment when my two new toys didn’t work together. Here’s how to make the Pi1541 and fast load cartridges play nice together.

By default, the mode the Pi1541 boots into isn’t compatible with fast load cartridges. You have to enable an option to load the file browser off a disk image called FB.D64, and then the two devices work together the way you probably intended.

Making the Pi1541 compatible with fast load cartridges

Pi1541 and fast load
I got this vintage Epyx Fast Load cartridge at a good price, but it didn’t work with my Pi1541 at first.

The Pi1541 boots into a mode that mostly emulates an SD2IEC device when you first power it on. But unlike the SD2IEC, the Pi1541 in this mode isn’t compatible with fastloaders. At least it isn’t compatible with cartridge-based fastloaders. It malfunctioned even if I disable my Epyx cartridge from its built-in menu. As best I can tell, it’s incompatible because making the Pi1541 compatible in SD2IEC mode would require mixing two legally incompatible open-source licenses.

That’s a shame. But there’s a workaround that doesn’t involve adding a disable switch.

To make it work, you have to copy the disk image fb.d64 into your SD card’s 1541 directory. You can download that image from the Pi1541 home page. It’s in the downloads section.

Next, you edit your configuration to automatically mount that image when your Pi1541 boots up. Edit the options.txt file on your SD card, whether from the Raspberry Pi or by mounting your SD card in your regular computer. Scroll down to the line that contains the words AutoMountImage = fb.d64. Uncomment this line by removing the two slashes at the start of the line, then save the file.

And that’s it. This easy-to-overlook option makes your Pi1541 compatible with an Epyx Fast Load, Action Replay, or Final Cartridge. Presumably it will work with other fastloaders as well. The configuration file calls out those three three (that’s what the comment about EFL, AR, and FC means), and I happen to own an Epyx Fast Load, so I know that combination works.

One more trick to make the Pi1541 work better

I recommend doing one more thing. There’s an option in the configuration file that by default makes the Pi1541 change back to its root directory when the computer resets. It doesn’t seem to work when you do a soft reset, such as when I push the reset button a previous owner kindly hacked into my Fast Load cartridge. The way I work around this is to copy the FB64 file to my disk images, as long as there’s room.

I find this faster and easier to do from a PC than from the 64 itself, using a utility like Dirmaster. Be sure to modify copies of your D64s in case anything goes wrong. Open the FB64 disk image, then export the FB64 PRG file using the file menu. Then open your destination D64 image and import the FB64 PRG file you just exported. Then copy your modified D64 images into the 1541 directory on your SD card.

Now when I’m done playing Jumpman and want to play something else, I can just hit my reset button, then LOAD”FB64″,8 and run it to get the option to change to another disk image, without having to power-cycle stuff unnecessarily.

The experience isn’t exactly like having a hard drive on a C-64 would have been. But I imagine it’s fairly close. And in some ways, better.

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One thought on “Pi1541 and fast load cartridges

  • June 1, 2021 at 2:06 pm

    Thanks for the article, I just recently got a Kung Fu Flash cart, and had run into this issue when using Epyx Fast Load and using my Pi1541. Thanks again!

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