Pi4 wont boot

Question

got my pi4 but it just can't boot

2 long green flash follow by 8 short flash, and even fail to show the rainbow screen.

Try different SD card or enable the hdmi_force_hotplug=1, both not work

The card is OK to boot a pi3 so probably not the SD card problem.

Try update bootloader still the same

Any ideas ?

colporteur · Answer

I see by your profile you are newly minted in the E14 Community, welcome and I do hope someone can help.

The test of moving the SD card to another host and it booting is a solid move to troubleshoot the SD Card. The next issue would be power? What are you using for a power supply. Power has caused me problems in the past.

Are you able to display video through the boot process? There is a pattern to the boot process that the display might offer some insight.

colporteur · Answer

I suffer from familiarites. I assume when a person gets involved with SBC or microcontrollers, they become so immersed that they become infected with the same condition. It causes the wearer to narrow focus. Some things become less important yet may in the end cause problems. As DW dougw points out in his post, I assume when you suggest video connected, that means a correct cable, that is know to work, is connected from the correct video port to the correct video input and that input is selected to display content. Any number of things in that scenario can be wrong and as a result no video. When I say video doesn't work, it is a know tested path used to confirm a problem. I have been told and continue to fail in reducing the knowledge of the individual. If I get the impression you have knowledge, I don't challenge it. Unfortunately, that bites me in the *** more often than I like. Yeah, they spin a good story but have no idea what they are talking about. I have a proliferation of Pi's that makes a simple won't boot, relatively easy to isolate. I also have a wealth of experience that I can draw on to help get over humps. I accept there are scenarios that exist where shite doesn't work. A know working SD card in a known working Pi, moved to a Pi that doesn't work to me points to the hardware. Now I confess I have SD card that generate chronic problems. They work on some stuff but not on other. Technology for fun is a ***.

cptang · Answer

Hello Sean and Gary, Thx I do use a Pi4 power supply from seeed studio . I also try another pi 4 power supply though but same result. I find nothing output to the monitor. Also try “Raspberry Pi 4 EEPROM boot recovery”, it seems work since i saw the green LED blinking continuously then off. Nevertheless the LED flash code is attached below.

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gdstew · Answer

Sure looks like 2 long and 8 short to me! It would be much more helpful if the documentation was complete with regard to these error codes.

And I did try to find it. Here is what is what I found on the official Raspberry Pi web site:

Long flashes	Short flashes	Status
0	3	Generic failure to boot
0	4	start*.elf not found
0	7	Kernel image not found
0	8	SDRAM failure
0	9	Insufficient SDRAM
0	10	In HALT state
2	1	Partition not FAT
2	2	Failed to read from partition
2	3	Extended partition not FAT
2	4	File signature/hash mismatch - Pi 4
4	4	Unsupported board type
4	5	Fatal firmware error
4	6	Power failure type A
4	7	Power failure type B

colporteur · Answer

No video output is disconcerting and would give me causes to abandon further troubleshooting. An inexperienced users with a new Pi may have difficulties. Once you eliminate the normal stuff, power and SD card there is not much else in the users domain to troubleshoot.

Have you open a trouble call with the vendor? I suspect you are at that point. Especially considering it is new.

kmikemoo · Answer

cptang I'm going to go out on a limb and recommend reflashing the SD card with the latest Raspberry Pi OS. It's a long shot but not all generations of RPiOS are created equal. It's one more thing you can say you tried before getting the return authorization from your supplier.

DAB · Answer

Go get the latest (July) RPi Magazine. They describe what the flashes mean. DAB

gdstew · Answer

I checked it out and the two long eight short sequence is not on the list. There is only one eight short flash sequence listed and it is after zero long flashes for a SDRAM failure. The next closest is 4 long and seven short for a Power failure type B. There is no explanation of what that actually means and there is a Power failure type A that also lacks an explanation of what it is or what the difference between them is. I went to the link at the bottom of the last paragraph (magpi.cc/blinkwarnings) and it doesn't offer any explanation either.

gdstew · Answer

This is very true. The Pi 4 specifies a 15W (5.1V @ 3A) power supply. The official Pi 4 power supply meets this spec as do several other suppliers

and a few offer slightly higher output voltage, usually 5.2V. If you go the with something other that the official supply make sure it is using 18 AWG

wire in the power cable so it can supply the 3A without significant voltage drop.

kmikemoo · Answer

colporteur I did think on the fact that the SD card worked in another Pi, but it may not have been another Pi4. I think back on a Pi3 that would not boot so I threw it in the trash and bought a replacement. Not satisfied, I dug the old one out of the trash and kept researching. There was something in the newer versions of the RPiOS that the Pi3 wanted to see and it wasn't on the OS on my SD card - so I updated it with the (new to me) Raspberry Pi Imager and WHOA!!!!, my rescued RPi3 worked just fine. If the other Pi was a Pi2 - because we all have at least one of those still about, one might get misled that the OS is sufficient for the Pi4. <- Maybe. I haven't tried to validate this, ergo... going out on a limb. <thumbs up>. Edit: Reread the original post. CP did say the other Pi was a RPi3. Still worth trying - IMHO.

dougw · Answer

What video port were you using? - the video didn't show a video cable. (the port nearest the power connector is the boot video port) This isn't the reason for the odd flashing pattern, just included in case it helps someone. More tips on Pi4 boot issues: https://www.youtube.com/watch?v=JYrGoLbiyj8&ab_channel=EVMYT

colporteur · Answer

Just received this link. https://magpi.raspberrypi.org/articles/become-a-raspberry-pi-genius?mc_cid=921bf53532&mc_eid=d5007f545a describes boot and LED indications.