FIP Customizer version 1.02 has just been uploaded. Details are in the file’s Changelog.
Alexey added his work was done through patching the DLL file that is part of the device’s DirectOuput service.
Also, maximum custom message size is 11 characters in the x64 bit version and 9 characters in the x86 version. For font names, similar limitations to allow 7 and 5 characters respectively due to the amount of space available in the DLL file.