I suspect that my RPi4 Ethernet port has died. Both the orange and green LEDs are permanently on, and there’s no sign of the RPi4 on my home network.
I’ve changed cables and switch ports to no effect, and also tried Ropieee and Dietpi SD cards. Even without any SD card installed, these LEDs are permanently on, and the small green LED on the RPi4 flashes in a cycle of 4 times, followed by a pause. This apparently tells me that the bootloader in the RPi’s eeprom is OK.
Thoughts?
I had a similar experience, it turned out to be the SD card ( after I had bought a new Pi)
I found another card, Etchered Roipeee and rebooted
Worth a try
Thanks Mike, I flashed yet another SD card, and I’m back up and running again. Strange that I couldn’t get the SD card with DietPi on it working either - perhaps I have two faulty SD cards. And a new RPi4 will be arriving tomorrow - sigh. Oh well, I can find a project to throw on it, I suppose.
Music in the bathroom?
Nope, but perhaps the garden beckons…
Sounds familiar . I got mine to work after the new Pi was delivered , still I got an upgrade to Pi4 and have a spare Pi3. Maybe Pi’s have built in AI that hates being replaced 
These pesky little cards are a pain …
Same here, but i’ve seen it more often on the SOtM sMS-200 and Allo USBridge devices than on Pi’s. (Perhaps it’s my penchant for DietPi that saves the day? All system scrobbling to RAM)
I actually bought the RPi4 to replace my USBridge (which I’ve since sold) - sonically, I couldn’t tell the difference between them. The USBridge was powered on 24/7, but it would require a reboot every few months because it would stop responding for some reason.
My RPi4 bridge to Meridian Prime runs 24/7, but reboots once a week. So far, no problems.