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1 June 2024

MEGA65 User’s Guide Chapter 4 - Configuring Your MEGA65

by Steven B. Combs, Ph.D.

Welcome back to another installment of the MEGA65 User Guide series! Today, we’re diving into Chapter 4: Configuring Your MEGA65. Buckle up, because we’re going to unlock the customization potential of your MEGA65 by exploring the configuration utility, SD card setup, and downloading files from the MEGA65 FileHost.

But wait, there’s more! Remember, this series is a treasure trove of YouTube videos and companion blog posts to enhance your experience. The blog posts are packed with all the links, errata, and resources you need to supercharge your MEGA65 journey, while the videos provide the visuals to make everything crystal clear.

So, whether you’re following along with the blog, watching the videos, or diving into the MEGA65 User’s Guide, you’ve got a complete, all-in-one resource at your fingertips. Let’s configure your MEGA65. All the links to access these additional videos and blog posts are in the video description below.

MEGA≡65 User’s Guide Series Page



Below are the links you need to help you get the most out of your MEGA65.



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Title: MEGA65 User’s Guide Chapter 4: Configuring Your MEGA65


  1. 2024-07-07: Gürçe noted that I referenced the SD card bundle that did not include all the demo disks. I’ve updated the OBTAINING THE BUNDLED SOFTWARE section to reference the ALL INTRO DISKS - Public package.
  2. 2024-07-07: Dan reminded me that, “that Filehost will only show you the “Kernal ROM - Stable” if you are signed in with your Filehost account and you have redeemed your owner code (the code on the piece of paper that came with the computer). If you only see Kernal ROM diff files - Stable, you’re either not signed in or haven’t redeemed your code. Feel free to ask for assistance on the MEGA65 Discord.”
  3. 2024-07-07: Dan dropped another tip regarding the SD card bootstrap process; “The release core has the corresponding ROM bundled along with those other SD card files. If you’re populating the SD card from a release core, it’ll install the ROM and you won’t need to get it separately. (The message is different.) The core slot entries that say “14 files” in your example are these. You were prompted to install the ROM file separately because you selected a non-release core for the files (“12 files”) which did not have the ROM bundled, probably from a late test version. So the tip about signing into Filehost only applies when you get to the Upgrading chapter in your next video. You’ll need to be signed in and have redeemed your owner code to download the release package with the core that bundles the ROM file in this way. The release package download also contains the SD card files separately (including MEGA65.ROM), so you can update an SD card without formatting it by replacing the system files manually.”


First up is the Configuration Utility. This powerful tool allows you to fine-tune the settings of your MEGA65. Here’s how to access it:

  1. Power off your MEGA65.
  2. Hold the ALT key.
  3. Power on the MEGA65 back.

You’ll see a menu, called the MEGA65 MEGA OS Hypervisor, with several options. Press 1 to enter the Configuration Utility. This utility contains six pages of options: input, chipset, video, audio, network, and done. You can move between pages using the and cursor keys and move up and down on a page using and cursor keys. Press RETURN or SPACE to toggle a setting or change a value. Let’s see what options we have by starting with the input page.


The Input page allows you to configure mouse settings for the two peripheral ports. Here’s what you need to do:


Select the type of mouse connected to each port; of which there are two, Joy 1 and Joy 2. Options include:

NOTE: Don’t have an original Commodore Mouse? Consider a mouSTer adapter. This adapter allows you to use a modern mouse to emulate an original Commodore mouse.


Each Joy option includes a de-jitter setting. This adjusts the sensitivity in Commodore 1351 mouse mode to avoid jitter in the mouse pointer. Leave this set to on when using a 1351 mouse in normal mode.


The Chipset page configures several features we’ll look at next:


We set up the real-time clock in an earlier chapter, but if you need to change it again, follow these steps:

When you press RETURN, the settings for the RTC will update immediately. This is not true for other settings. You use the DONE screen to activate these changes. We’ll cover this later.


You can choose which Direct Memory Access (DMA) controller to use on the MEGA65:

TIP: Want to know more about the differences? Ask the MEGA65 Discord community for examples of why you might choose the F018 DMA controller.


Select where the MEGA65 looks for a boot disk when switched on:

For convenience and speed, I recommend you use the SD Card.


Toggles long filename support on the SD Card. Leave this option enabled unless you find you have issues reading filenames longer than 11 characters.

TIP: At the bottom of each page is a reminder that you can press the HELP key to view help for each page of options.


The VIDEO page configures video settings. These are identical to the onboarding options when you first set up your MEGA65.


Toggle between PAL and NTSC modes. If you have an original CRT monitor using the VGA port, choose the option based on your display’s compatibility. PAL (Phase Alternating Line) and NTSC (National Television System Committee) are analog television standards that determine the resolution and refresh rate of the video signal. PAL is common in Australia, Africa, China, Europe, and Australia, while NTSC is common in North America, South America, the Philippines, Taiwan, South Korea, and Japan.

When using a modern digital display, the MEGA65 can emulate either PAL or NTSC mode but there are performance differences:

NOTE: You can conveniently toggle this setting using the Freezer menu.


Enable or disable digital video sound. Enable ENHANCED (WITH AUDIO) if your display has built-in speakers for integrated audio. In rare cases, your DVI display may require you to select the DVI ONLY (NO AUDIO) option.


Enable to make the picture look like a vintage Cathode Ray Tube, or CRT, display for a nostalgic experience. This will add software-produced scan lines to the display.


Time to configure the MEGA65 sound system.

TIP: You’d only need to make changes if you have specific use cases. I recommend the defaults.


Choose between stereo and mono(aural) output. Choose STEREO for an immersive sound and to activate the ability to use the Freezer’s audio mixer to pan the four MEGA65 Sound Interface Device, or SID, chip’s sound left and right.

Choose MONO for single SID channel simplicity or specific retro software use cases.


The MEGA65 can emulate either a 6581 or 8580 SID chip. Commodore installed the 6581 in early Commodore 64s. Later, Commodore used the 8580 in newer C64s and the C128. Why would you use one over the other? The 6581 had flaws that some software exploited for better sound. If you run into these games, you can experience them as the programmers intended on the MEGA65.


Switch the stereo mix to use the opposite speakers. Handy for a quick fix in speaker placement.


Controls the amplifier connected to the 3.5mm audio jack. Set this to ON when using headphones or OFF for line-level signal connected to powered speakers or capture devices.


Unlike earlier Commodore computers, the MEGA65 includes an Ethernet port, but it does not include a hardware-assigned Media Access Control, or MAC, address. Every device on a network must have this unique 12-character alphanumeric identifier. Here’s how to set a MAC address.


Networking features will not function with a MAC address set to all zeros, which is the MEGA65’s default. If the MAC address is all zeros, press the R key to generate a random address.


Once all settings are correct, head to the DONE page for the following options:


Abandon the modifications you’ve made to the settings pages.


Reset all settings to their defaults. Consider using this option when you have issues with the MEGA65.


To go back to the screen that appeared when you first took the MEGA65 out of the box and powered it on.


Save all current settings and exit the Configuration Utility. The MEGA65 will prompt you to “power-cycle.” Switch the computer off, wait a second or two, and then switch it back on. Your new settings are now in effect.


Your MEGA65 comes with two SD card slots, each serving different purposes and offering flexibility to manage your data and system files. Understanding how to use these slots effectively will enhance your experience.


Let’s look at each SD card slot.


Located inside the case, you use this slot for system files and bundled software. The MEGA65 comes with an internal SD card pre-populated with the operating system and essential software, providing a seamless retro experience right out of the box. Leave this card in place to maintain a seamless and authentic retro experience. This SD card is configured to boot the system and run essential software efficiently. Since it holds critical system files, avoid frequent removal or modification unless necessary for system updates or troubleshooting. I recommend you keep a backup copy of this internal SD card’s contents on your computer, or like me, in Google Drive.


This slot is accessible from the rear of the MEGA65 and is ideal for file transfers and regular updates. The convenience of accessing this slot without opening the case makes it perfect for moving files between your MEGA65 and other devices, such as your PC. This card is ideal for users who frequently update or add new content to their MEGA65. It’s also useful for backing up important data or sharing files with other devices. The ease of access makes it convenient to switch cards as needed. Use this slot for non-essential files to keep the internal card focused on core system functions.

Here’s additional, and useful, SD card information.


The MEGA65 can only use one SD card slot at a time. When you insert a microSD card in the rear slot, the system will automatically ignore the internal SD card. This feature allows you to switch between different configurations without physically removing the internal card.


For major system updates or changes to the operating system, use the internal SD card. For minor updates, software installations, or file transfers, the external microSD card slot provides the flexibility you need without disrupting the system’s core functions.


You can also transfer files over a local network. This is useful for large file transfers or frequent updates to the SD card. We learned earlier that our MEGA65 needs a unique MAC address and includes an Ethernet connection to connect to a network. That’s the first step; however, the MEGA65 team has also created network sharing tools to move files seamlessly between your MEGA65 and modern computers. We will learn more about this feature in Chapter 7. For now, let’s learn how to prepare a new SD card.


To prepare a new SD card for use with your MEGA65, follow these steps. It’s important to ensure you’re using a compatible SD card format to avoid any issues.

The MEGA65 supports SDHC cards with sizes between 4 and 32 gigabytes (GB). You should not expect older cards less than 4 GB, and newer SDXC cards larger than 32 GB, to function. They may…but don’t count on it.

IMPORTANT: You cannot create a compatible SD card on your personal computer. You must use the MEGA65’s built-in SD Card Utility. Why? Because the MEGA65 creates two partitions: a hidden partition containing MEGA65 configuration files, the Freezer menu options, computer freeze states, and a FAT32 Partition that contains system files and .d81 disk images.


The internal SD card is inside the case and accessible by opening the case or removing the trapdoor at the bottom of the computer. The external microSD card slot is conveniently on the back of the MEGA65.

NOTE: ALWAYS POWER OFF your MEGA65 before inserting or removing an SD card. This prevents data corruption or hardware issues.

To insert/remove an SD card, follow these steps:


Orient the SD card correctly with the label facing up, and insert the full-size SD card into the slot. Gently push the card in until it seats completely into place. To remove, grip the SD card by its sides and pull it out of the slot.


Insert the microSD card into the rear slot with the label facing up. Gently push the card in until it clicks into place. To remove, push the microSD card in the slot until it clicks. This will release the microSD card and force it out of the slot so you can grab it with your fingers.

Use high-quality, reliable SD cards to ensure consistent performance and longevity. I have links to the cards I use in the link section.

You can “bootstrap” a new system using just an SD card and the SD Card Utility. Handy if you have “broken” your SD cards. Let’s learn how to do this next.


The SD Card Utility will completely erase the contents of an SD card. While the utility will ask you to select an SD card to format, it’s a good practice to protect the internal SD card by removing it before using this utility. Use the following steps to load the SD Card Utility:

  1. Switch off the MEGA65.
  2. Hold the ALT key.
  3. Switch the MEGA65 the on.
  4. Select option 2 (SDCARD FDISK+FORMAT UTILITY). The SD Card Utility will open and scan for inserted SD cards.
  5. Insert an SD card to prepare in either the external or internal slot.
  6. Press R to re-scan for a card.
  7. Choose a card slot; 0 for the internal SD card or 1 for the external microSD card.
  8. Type DELETE EVERYTHING in all caps and Press RETURN to confirm SD card erasure and formatting.

You can abort the process by switching off the MEGA65; however, once the process starts, the SD Card is unusable until you restart the process.

REMEMBER: Formatting will erase all data on the SD card. Ensure you have backed up any important files before proceeding.

The SD Card Utility erases the SD card and creates two partitions. When finished, the utility prompts you to install the system files from a core. The core includes embedded system files, with filenames ending in .M65 and .ROM. Choose a core to use.

If you have an updated MEGA65 core in slot 1, select it. Otherwise, select the factory-installed MEGA65 core in slot 0. If you just received your MEGA65, slot 0 is the only option. The utility will use the chosen core to copy files to the FAT32 partition, making the card usable immediately, or “bootstrapped.” At the prompt, reboot the machine.


The MEGA65 Filehost contains a variety of files for your MEGA65 including ROMs, cores, and hundreds of games, demos, and applications produced by the MEGA65 community. It also includes the bundled software from the original SD card.

If you no longer have the bundled software files, follow these steps to download and transfer them to an SD card:

  1. Visit the MEGA65 Filehost at files.mega65.org.
  2. Download the bundled software files called ALL INTRO DISKS - Public.
  3. Unzip the software download package (usually a double-click on the file).
  4. Copy the files inside the folder to the root area of your new SD card.

The SD Card is now ready to use.


Time to close the user’s manual on Chapter 4. Want to ask questions, make suggestions, and get additional insights? Visit my Buy Me A Coffee page so you can learn how to join my Discord. I’ve created a separate channel for this series so the conversation can continue. You can get access to the Discord by joining at the Commodore VIC-20 level for only $2/month. Of course, I have other Commodore-inspired levels with additional perks, so check those out too. Get to configuring your MEGA65 and see you next time. 🕹️ retroCombs, OUT!