The C64U comes with a function to online search and install software labeled as 'CommoServe'. This is actually a subset of a larger databae known as 'Assembly64'.

The following is about getting access to this large database on the C64U and is quite technical. This also something that was not the intention of Commodore that people would do it. If it works now it can that will not work anymore later.

• Jussi offered when making that post access to a proxy server free to use to make it work. There is also the information on github to setup your own proxy server
  • The information about the proxy server of Jussi ( as is)
    • To use it, put static IP on your C64U and for DNS address use 157.180.85.223 which is my server. That will spoof assembly64 address to point to my server and my server then alters request headers so you get REAL assembly64 files and not commoserve. To revert back, put your own DNS address instead.
  • Original FB-post about this with detailed instructions
• https://github.com/jusii/c64u_server_switcher - Offers the option to switch between CommoServe and Assembly64 from the GUI of the C64U

• FB-post from Dean W. about how he changed the default BASIC boot GUI
  

Service to change the look of the default BASIC startup screen.

• ⇒ https://c64.pro or https://c64kernal.com/
• Website where you can upload your own ROM file. The service will modify the file with the selected esthetic option. After payment of $3 you can download the file and activate it. - Except some designs who are free of charge
• Works also with JiffyDOS and DolphinDOS

Example of the look after modification. More designs are available.

This is a replacement for the original C64 system font. You can use it with VICE or in a real C64 with a character eprom. 6 pixel uppercase height, better readability, mostly closed inverted text, consistent x-hight.

• https://csdb.dk/release/?id=187321

Firmware is a type of software program embedded into hardware devices to help them function smoothly and effectively. Firmware is installed directly onto a piece of hardware during manufacturing. It is used to run user programs on the device and can be thought of as the software that enables hardware to run.

• Official firmware by Commodore - If you have just recently received your C64U, you may want to update your firmware from 3.14 to 1.1.0 to improve the functionality of your Commodore 64 Ultimate. Note that Commodore decided to change the version numbers of their firmware to emphasize the difference between the firmware for Gideon's line of Ultimate devices and the Commodore-branded ones. Firmware versions for the C64U are, in order of newness, 3.14, and 1.1.0, where 1.1.0 is the most recent one. Note that firmware 1.0 was really just a renumbered firmware 3.14.

• Spiffy Patch - Adds several QOL features and fixes a bug or two on top of the most recent official Commodore firmware. Offers a temporary “soft patch” option that is reverted after a restart of the computer. Can also be flashed permanently for those that wish to do so.
  • Replaced Commoserve with Assembly64 for a larger software collection.
  • Additional hotkeys for reset, reboot, power cycle, power off, joystick swap, set/go to home, and show dev log.
  • Custom branding of the Ultimate menu
• PRKL patch - Mainly the Spiffy Patch with very good USB Mouse and keyboard support added in, plus a few under-the-hood fixes. Adds scroll wheel support for USB mice. Great for use with GDOS64 and MicroMysX0 mouse driver!