I am installing a TFT24 v1.1 and it appears to be functioning in the 12864 modes with the exception of the top two lines which are gibberish.
I have attempted to block both the boot and the custom boot screen but that does not fix it. It's working with Marlin 2.0.x bugfix and also tried 18.104.22.168. I am using a spare Bigtreetech SKR v1.3 with USB power and only the two thermistors connected, which are being read. Perhaps I installed the firmware wrong in the TFT24, but I don't think so.
I have determined that it is not a Marlin problem as the gibberish is immediate before Marlin even comes up 3 seconds later (about).