Upgrade THEC64 Mini

Firmware upgrades for THEC64 Mini provide new features and/or correct any technical issues. We always recommend that you upgrade to the latest version of the firmware.

Ensure that your USB memory stick is formatted using FAT32 (with MBR), else your upgrade file will not be detected. Please ensure that when updating, THEC64 Mini only has one joystick and one USB memory stick plugged in to your console. We do not recommend that you upgrade with a USB hub. See the FAQ for further details.

Visit here for the firmware upgrade details page for THEC64.

Version 1.5.2 – Changes and additions


To enable REU support you can use either a filename flag or a CJM file parameter. Note that REU support does not work with VIC20 software.

To select using a filename flag, use one of the following:

R5 = 512K REU enabled
R2 = 2MB REU enabled
RM = 16MB REU enabled
For example:


See the user manual for further details on the use of filename flags.

To select with a CJM file, use one of the following parameters:
reu512 = 512K REU enabled
reu2048 = 2MB REU enabled
reu16384 = 16MB REU enabled
For example:


See the user manual for further details on creating CJM files.

To switch the joystick in use between joystick port 1 or port 2 when running a C64 program, press and hold the joystick ☰ button, and then pressing joystick Ⓐ for port 1 or joystick Ⓑ for port 2. This will override the J1 filename flag or CJM primary port setting, if either are supplied.

To perform a soft or hard reset, or cartridge freeze on THEC64 Mini, you will need a compatible USB PC keyboard.

A soft reset may be performed by holding the left shift key and pressing F12 when in classic mode. This will usually leave most of the C64 memory in tact.

A hard reset is done by holding the left shift key and the Windows key and pressing F12 when in classic mode. This will reset the C64 memory.

A cartridge freeze is done by holding the right shift key pressing F12 when in classic mode. If you are running a suitable cartridge image, such as a Super Snapshot or Action Replay, it will instigate the inbuilt cartridge features whilst leaving the C64 memory in tact.

Changes from previous versions

How to Upgrade

    1. Check the current firmware version on THEC64 Mini by selecting the SYSTEM icon from the OPTIONS on the HOME screen, and then choose System information from the menu. Look for the Build version (e.g. theC64-1.2.0-argent)
    2. Check that the latest version linked to above is greater than the version installed on your Mini
    3. Download and save the file (e.g. theC64-1_4_0.bin) to your USB memory stick. Don’t place the file inside a folder on the stick or rename the file. If you do, THEC64 Mini won’t find the upgrade
    4. Insert the USB memory stick into an unoccupied USB port on THEC64 Mini
    5. Select the SYSTEM icon from the OPTIONS on the HOME screen on the Mini, and choose System Information
    6. The upgrade file is detected and you are asked to Close or Apply
    7. If you choose not to upgrade at this time, select Close and press FIRE, or just press the MENU button on the joystick If you Apply the upgrade, the following screen will appear showing the upgrade process:

After a successful upgrade, your Mini will shut down and restart automatically.

You can check the firmware version afterwards by following point (1) above.

Note that you cannot install a firmware earlier than the build version currently installed.