Exactly, there is no need to make a connection between the pc and the mini 801.
I used the Quick FS Editor to swap the startup/shutdown pictures with the ones I wanted. And I also opened every poweron/poweroff .pcm file I could find (6). I just opened them and did nothing else.
RomKitchen created a new firmware file for me, and the only thing else I had to do is to rename the file with the correct file name.
After that I copied the new firmware file to a formatted SD card, after inserting the SD card into the mini 801, I pressed the startup button and approved the firmware update question. The mini shuts down by itself and after pressing the startup button again everything was working as desired.
I'm certainly no expert, but after reading all the available information on RomKitchen 07 and after a few times practicing with different firmware versions I was confident enough to try it out.
To write everything down in English is still a bit tricky for me, but I hope it helps.