Was thinking of creating a new thread, then a pop-up appeared saying that the title I wanted to choose(Raspberry Pi 3 B+ Installation and Support Status) was similar to this topic, so I'll just post here first then.
The images provided here(stable releases for bcm2710 subtarget) are not really ready for the 3B+, but are more for the 3 non-Plus? Would that mean that for now the development snapshots should be used? I tried burning the ext4-factory.img onto a 4GB micro SD card, but when I put the card in and powered up the Pi, the ACT LED blicks 4 times at one rate, then blinks faster for another four times, which repeats.
Currently I do not have a serial cable, but I can get it to use it if it is needed. Does the Pi 3 B+ always show a rainbow screen when booting if connected to a screen, regardless of whether the system is supposed to be headless(ie Regardless of image burned onto the SD card, as long as a screen is connected, the rainbow screen will show on the screen)?