http://cccpastefzuz6unowzgjtdwmxwjfgf5za7owwci3b2zys4jmc3xjszad.onion/cccea7c18ebdb7dd
Sadly the package e2fsprogs with the tools for ext4 filesystem is too large to fit in 4 MiB devices.
Afterwards, open the folder bin inside the Image Builder folder, then open the target folder, then the folder you find in it (it has a device-type-specific name), and then inside a folder called generic and you should reach the flashable images.