Neither DreamPi image booting on Pi 3 Model A+ (Gave up and got a 4B)

[Spike Belfrey]

Trying to migrate over from using PC-DC to a Pi, but strangely neither the regular nor Pi 4 version of DLE 1.9 are booting.
The green light on the Pi turns on and flickers like normal, but unlike other non-booting issues I don't get a rainbow through HDMI (or AV if that port actually works with a yellow to yellow cable), but like other similar topics the official Pi OS image works without issue.

I've also noticed that when I try to connect the USB modem with either DreamPi image flashed, neither green light turns on, so as far as I can tell, it's hanging as early as possible. I've tried using an old 4 GB Kingston microSD and a much more recent 64 GB Micro Center one, flashing with Win32ImageWriter and the software linked on the Pi site, with all having the same results with both DreamPi images not working and the official one working.
(Along with Windows giving a error saying I should format a non-existing drive once the writing, but I assume that's Windows being stupid about there being a second partition written to the microSD by the images)

I'm new to Raspberry Pi, so I'm not sure what else I can try besides asking you folks.

Edit: I realized that the green light on the Pi flickering is not normal. It doesn't do that with the regular Pi image, it blinks some and then once it starts booting it goes solid green, but I'm not sure if that narrows down the potential problem any more

Edit 2: I just exchanged it since I could and got a 4 Model B, and that worked with no issues. Not that that's a real solution to the problem, but I didn't want to leave the thread unupdated.

[Spike Belfrey]

I haven't solved the issue yet, but I did find that the Pi's green light flashing is giving a code of 4 long beeps and 7 short ones, which according to this page on the Pi site means "Power failure type B". Not very helpful given I've been using the same cord and plug the entire time.

I also tried to replace the start.elfs in the SD flashed with the Pi 4 DreamPi image, and with specifically just start.elf from the Nov 19th Pi OS Lite, it actually boots, with all the services from DreamPi seeming to start up (usually). After setting up Wi-Fi on a 2.4 ghz network though, it doesn't seem to be ever turning on the second light on my modem despite everything indicating the Pi is connected; I can't really rule out that it's not because start.elf is from a completely different version though since I don't know what it does in the first place.

[Scrivani]

Looks like you found a solution for the boot part.

About second light missing, please give me your discord or text me on Discord, my username is quite obvious: Scrivani

Then we can see the logs and find out what is going on.