CM1 with StereoPi v0.9 gets stuck in rainbow screen during bootup

StereoPi hardware discussion
Post Reply
HelplessPineapple
Posts: 7
Joined: Wed Apr 27, 2022 5:48 pm

CM1 with StereoPi v0.9 gets stuck in rainbow screen during bootup

Post by HelplessPineapple »

Hello,

I am using a CM1 with the StereoPi v0.9 slim edition with the SMD header and dual USB socket soldered onto it. The CM1 eMMC has already been flashed with a custom Raspbian image. It works perfectly fine with the Raspberry Pi Development Board.
But when I try to boot it with the StereoPi board, the display gets stuck on the rainbow screen and I also get no messages via the UART0 terminal.

I checked all voltages (5V, 3.3V & 1.8V) which are accurate and stable and my power supply delivers up to 3A. According to the Ninja DIY tutorial, I changed the R15/R17 resistors, so that the board is powered from 3.3V. But I read that information AFTER powering the CM1 with the StereoPi board up the first time, so the CM1 got initially powered up with 5V. But with the RPi development board, the Compute Module works still fine.

I have no idea, what I could try next. Has anyone an idea, what could be a possible solution?

Thanks for any help in advance!
Last edited by HelplessPineapple on Sat Apr 30, 2022 12:51 pm, edited 1 time in total.

User avatar
Realizator
Site Admin
Posts: 852
Joined: Tue Apr 16, 2019 9:23 am
Contact:

Re: CM1 with StereoPi v0.9 gets stuck in rainbow screen during bootup

Post by Realizator »

Hi HelplessPineapple,

If CM1 is working fine on RPF's IO board - looks like it's alive.

The R15/R17 switching just connects another output from the DC-DC chip (schematic) to the CM's VBAT pins. I don't think that 5V powering of CM1 would damage LM26420.

Could you please check a few things:
1. The micro SD card is not inserted into the StereoPi, right? CM1 was always eMMC-equipped (AFAIK).
2. What's the position of the BOOT jumper on your board?
3. Try to "switch" powering mode. I.e. if you are using JST connector (default and recommended for StereoPi v1), try to power it by micro USB connector.
Eugene a.k.a. Realizator

HelplessPineapple
Posts: 7
Joined: Wed Apr 27, 2022 5:48 pm

Re: CM1 with StereoPi v0.9 gets stuck in rainbow screen during bootup

Post by HelplessPineapple »

Hi Realizator,

thanks for the quick response! :)

1. No micro SD card is inserted into the StereoPi.
2. The BOOT jumper is open (no bridge inserted into it). Only when new firmware is loaded into the eMMC, the jumper is inserted (which does work very well)
3. I already tried both options - the result is the same.

As I have another CM1 with a very old raspbian image, I put it into the StereoPi and it booted perfectly fine!
So I thought maybe it's due to some hardware damage of the first CM1 module and flashed my custom Raspbian image to the second CM1 - resulting in the same behaviour: a rainbow screen.
Therefore, I tried multiple Raspbian images (jessie, buster), which also resulted in a rainbow screen. Flashing the eMMC with the StereoPi board also works fine. So, both CM1 do not work anymore with the StereoPi. Does the hardware of the StereoPi has any influence on the booting process itself?

Thanks for your help, I really appreciate it ! :)

HelplessPineapple
Posts: 7
Joined: Wed Apr 27, 2022 5:48 pm

Re: CM1 with StereoPi v0.9 gets stuck in rainbow screen during bootup

Post by HelplessPineapple »

I have tried multiple Raspbian images again and the CM1 sometimes boots up regularly with some of them.
For example, it works from time to time with "2022-04-04-raspios-bullseye-armhf-lite" and "2019-09-26-raspbian-buster-lite", but not with "2020-02-13-raspbian-buster-lite" or "2019-04-08-raspbian-stretch-lite".
I checked the 3.3V and 1.8V with the oscilloscope and the voltages stay very stable during the whole boot-up phase.
Do you have any idea what could be causing this behaviour?
Thanks for your help!
Last edited by HelplessPineapple on Thu Apr 28, 2022 11:49 am, edited 1 time in total.

User avatar
Realizator
Site Admin
Posts: 852
Joined: Tue Apr 16, 2019 9:23 am
Contact:

Re: CM1 with StereoPi v0.9 gets stuck in rainbow screen during bootup

Post by Realizator »

wow, HelplessPineapple, your case looks more and more interesting :-)

Am I got you right, that:
1. Your second CM1 with the very old OS was able to run succesfully on the StereoPi
2. After reflashing 2nd CM1 with the newer OS, it stop booting too
3. Both 1st and 2nd CM1 are able to boot succesfully on CMIO board, right?

Also, is your custom image using any kind of overclocking and CPU parameters settings?
HelplessPineapple wrote:
Thu Apr 28, 2022 8:25 am
Does the hardware of the StereoPi has any influence on the booting process itself?
Both CM1 and CM3 are "simple" in comparison with CM4 (without the EEPROM), and the only thing for StereoPi to do is to power them up correctly. Also, by powering them from the PC (by the micro USB) you are disconnecting the USB/LAN chip, i.e. removing the "peripheral" device.

If we consider the hardware (power) issue, I see two things here:
1. Something connected to the StereoPi is consuming extra power. Please disconnect everything if possible
2. Short-circuit (metal dust or tiny piece of the copper wire somwhere).
3. DC-DC chip is partially damaged. For example, it gives you 3.3V with no load, but after powering StereoPi up it falls to lower voltage (like 3V or 2V).
4. Please look inside your USB A connectors on the StereoPi . In some rare cases inserted USB dongle can bend internal contacts and short-circuit USB's power line to the data line. Are they ok?

p.s. Once upon a time (at the RPi 1 epoch) there was a trick of adding a "boot_delay=1" command to the config.txt for fighting the rainbow issue...
Eugene a.k.a. Realizator

User avatar
Realizator
Site Admin
Posts: 852
Joined: Tue Apr 16, 2019 9:23 am
Contact:

Re: CM1 with StereoPi v0.9 gets stuck in rainbow screen during bootup

Post by Realizator »

HelplessPineapple wrote:
Thu Apr 28, 2022 9:18 am
Do you have any idea what could be causing this behaviour? Could it be an unstable 3.3V or 1.8V power supply during bootup?
At the boot time the power consumption can jump, right. I guess this old trick (boot delay) was used for this purpose. I.e. this delay pushes another consumption peak (eMMC aggressive read) for 1 second, and this helps system to stay stable.
Eugene a.k.a. Realizator

HelplessPineapple
Posts: 7
Joined: Wed Apr 27, 2022 5:48 pm

Re: CM1 with StereoPi v0.9 gets stuck in rainbow screen during bootup

Post by HelplessPineapple »

I already tried the trick with the "X"-s boot delay, but sadly it did not work, although the delay gets detected by the Pi during boot-up.

Yes, the 2nd CM1 booted successfully with the StereoPi, that 's why I tried multiple Raspbian images with both Compute Modules. And both of them boot SOMETIMES with some of the images. Let's say it works approximately 3/10 times for the current bullseye image (when I disconnect and connect the power again).

That's why I also thought it could be something with the DC/DC converters, but when looking at the 3.3V and 1.8V voltage lines during the boot up phase the voltages stay very stable (+/- 100mV).

User avatar
Realizator
Site Admin
Posts: 852
Joined: Tue Apr 16, 2019 9:23 am
Contact:

Re: CM1 with StereoPi v0.9 gets stuck in rainbow screen during bootup

Post by Realizator »

Hmmm... You did try to use other PSUs, right?
Eugene a.k.a. Realizator

HelplessPineapple
Posts: 7
Joined: Wed Apr 27, 2022 5:48 pm

Re: CM1 with StereoPi v0.9 gets stuck in rainbow screen during bootup

Post by HelplessPineapple »

Yes, two different 3A Lab Bench Power Supplies and also via the MicroUSB Connector.

HelplessPineapple
Posts: 7
Joined: Wed Apr 27, 2022 5:48 pm

Re: CM1 with StereoPi v0.9 gets stuck in rainbow screen during bootup

Post by HelplessPineapple »

I tested the StereoPi board now with a CM3 ( after changing R15 & R17) and the board works perfectly well. So the problems only occur when using the CM1 boards.

@Realizator: Have you tested the StereoPi board already with a CM1 and validated that it works? In this case, I assume that there has to be a problem with the 3.3V from the DC/DC Converter.

I just want to be sure that it‘s a specific problem with my particular board and that a new StereoPi board will definitely work.

User avatar
Realizator
Site Admin
Posts: 852
Joined: Tue Apr 16, 2019 9:23 am
Contact:

Re: CM1 with StereoPi v0.9 gets stuck in rainbow screen during bootup

Post by Realizator »

Hi HelplessPineapple,

I just got tested SteroPi V1 with the CM1 (with the R15-R17 modification).

I used the latest Bullseye Lite image - it boots fine. I also tried to use Bullseye Desktop, but CM1's eMMC size is too small to fit the full image. I forced to record it, but the boot fails at some point with the filesystem error (as expected).

In both cases the board does not stuck on the first boot stage.

Is your project has V1 "hardcoded" in it? You see, both StereoPi v1 (and CM1) are rare things now, and "are not recommended for the new design".
Eugene a.k.a. Realizator

HelplessPineapple
Posts: 7
Joined: Wed Apr 27, 2022 5:48 pm

Re: CM1 with StereoPi v0.9 gets stuck in rainbow screen during bootup

Post by HelplessPineapple »

No, but it‘s very hard to get a CM4 or CM3 right now. That‘s why we decided to use the CM1 boards.

If the CM4 will be available again, we will certainly use the StereoPi V2.

In this case, I suppose it makes sense to order a new StereoPi v0.9. Thanks for your help! :)

Post Reply