There are two steps to running the pico-mac emulator on the Fruit Jam: the pico-mac firmware and a Mac HFS image on a microSD card. The firmware is available as a precompiled UF2 in the GitHub repository in the latest release.

There are a few UF2 files to choose from with different resolution and overclock settings:

• 400kB or 4096kB (the latter uses PSRAM, and may perform slower overall but can run more software)
• 512x342 or 640x480 desktop resolution (512x342 is more compatible but has black screen margins)
• Overclocked or not (overclocked may run faster but may be less reliable)

Choose whichever one suits your emulation needs and proceed to put the Fruit Jam into bootloader mode. To enter the bootloader, hold down the BOOT/BUTTON #1 button (highlighted in red below), and while continuing to hold it (don't let go!), press and release the reset button (highlighted in blue below). Continue to hold the BOOT/BUTTON #1 button until the RP2350 drive appears!

Drag and drop the pico-mac UF2 file that you chose onto the Fruit Jam. The RP2350 drive will disappear. Next, you'll prep the microSD card.

microSD Card

You'll need to set up a Mac HFS disk image (.IMG file) on a FAT-formatted microSD card. There are a lot of disk images for Mac emulation on archive.org. The image below has been tested with the pico-mac emulator on a Fruit Jam and has popular shareware software included if you want to retreat quickly to the early 90's.

After formatting your microSD card, save your .IMG file onto it. If you want the image to be read-only, save it as umac0ro.img. If you want to be able to read and write to the image, you'll save it as umac0w.img. The .IMG file should be the only file on the microSD card.

Advanced Hackers Enter Here

If these steps to Mac emulation were too easy for you and you need to experience the trial and error of compilation and corrupted files then check out the options below for deep rabbit holes to burrow into in the pursuit of the ideal retro Mac experience.

Build-Your-Own pico-mac (Advanced)

There are build instructions for pico-mac if you want to build your own UF2 file instead of using the pre-compiled UF2 images. You will need the Pico/RP2040 SDK setup on your machine.

Customizing the Disk Image (Advanced)

If you want to customize your disk image, you'll want to run an emulator on your desktop computer so that you can load software from your file system onto it. The Mini vMac emulator works really well for this. Documentation about this emulator is available from the Gryphel Project.

When the emulator starts up, you'll load the disk image that you want to build on. You can install additional software onto the image and then try out the .IMG file with the pico-mac emulator on the Fruit Jam. You will need to rename the .IMG file as either umac0ro.img or umac0w.img on the microSD card.