Built my Zynthian but the screen display is upside down, ending with a summary and article on displays, I2C and SPI

Hi, I’ve just built my first Zynthian,
switch it on and the bootup screen is upside down.

Bootup message complains about bad interrupt.

OK, i’ll have to disassemble and start again - tomorrow.
But it’s good to know that i mostly did a good assembly job.

Could someone tell me what I likely did wrong,
so I can focus on this in my rebuild/debug.


Is it a kit, or a diy with your own bits?

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lcd_rotate=2 in display settings works for me…

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What wyleu said! You did it right!

This is the V5 kit.

It’s like I connected a ribbon cable backwards,
but I don’t see how I could have made that mistake.

Pretty sure you cannot make that mistake with those kinds of cables. You’re all good, just add that line.

I don’t recall needing to add that myself though, my V5 arrived a few months ago - did you do a fresh download of the OS image?

hi Wyleu

How do I access the display settings?
Do i need to edit the image on the SD card?

also, the machine fails in bootup
complaining about bad data interrupts.

which makes me think i must have
connected something backwards,
as it seems like it’s getting data it does not expect.

I’m using the 2023-11-02 image,
whch i downloaded the moment i ordered the kit.
I am very keen

hi Wyleu

which file in the image do i edit
to set the display settings?


Yes, I was a little vague but in my defense, I will offer that at this precise moment I can’t get a screengrab programme to work for love nor money on my Pi os 64 Desktop, so I’m not quite as visually verbose as I’ve previously been when answering questions, so hang in there…

Sounds like everything is ok if you’ve got any kind of legible picture on the screen, the orientation of the screen is done in software, and for that the answer is nearly always in webconf. It’s done like this so you don’t have to spend time editing files on the machine, and if there’s a well warn path appearing, that generally gets coded into webconf as well…

The discourse search can be a little bit mysterious but in this particular case it turns up good stuff with pictures…

I just searched ( the magnifying glass in the top right near your picture and put lcd_rotate into the search box).

It’s in the webconf display hardware settings. . .

This is a picture of one of my bespoke monstrosities settings, a machine named zynthian-amp2.local, do name them, they are pets not cattle . But it should be ok with whatever display you use, just be aware of what happens to the line if you start changing settings, the webconf might well replace it if you select another display type, and don’t forget to save.

Don’t slavish copy all this stuff, you should only need the lcd_rotate line, it’s just an emphatic display of where you configure this stuff. To be frank I look at it and have absolutely no recollection of quite which particular dragon we were fighting back then, which is probably as it should be. . .


This should do the trick, if not complain, and we’ll go round the loop till we get a sound sample out of you …

IT’s all very fair really…

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The official kit should work out-of-the-box with the latest stable image. There should be no reason to furtle with config. Did you allow it to complete its initial setup? Did you check the download was valid / complete? Did you mount the screen the right way round :grin: ?

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Burn the image again. Revise all the connections and try again.
It should work out t the box. No further config is needed. Really!

If you see the display rotated, the system is not booting ok. FYI, the display is mounted physically rotated in the V5 and the software takes care of this. If the system is not booting OK, then you will see the display inverted.


Greetings, Banjo. If from your viewpoint you’re still experiencing a problem and want to resolve it, please capture that message(s) by whatever method you easily can (cellphone photo, screen capture, whatever) and post them.

From your initial post, I can’t tell whether the Zynthian V5 successfully boots or gets stuck at some point during ‘startup’. If stuck, give us a picture of where it stops also.

The ‘upside down screen’ symptom could be hardware or software, let’s figure out what’s is going on before disassembling your Zynthian-fixing it.

hi @banjo I can imagine your frustration because this is such an unexpected behavior with official kit and current Zynthian SD image.

Absolutely, so, hey ho let’s go:

  1. Could you post a screen capture of zynthian’s webconf home page.

In webconf there is a terminal tool (you can do that through ssh too):

  1. Type the following commands and copy paste their outputs here :


=> shows the low level kernel (and then hardware related) messages

cat /var/log/Xorg.0.log

=> show the display (and also touch interface) server startup log

cat /boot/config.txt

=> show one of the base linux system hardware startup configuration file. Just to see if there is no mess in there

Other suggestions are welcome :wink:

Or the display is actually mounted upside down in the case? The connector should be by the cutout.


here’s a picture of the error message.
A little blurred, but readable,
(I’m a musician not a photographer)

I will reassemble it, taking special care
with the ribbons, but have been busy with gigs.

I am very comfortable with Linux (25+ years)
haven’t plugged in Webconf yet.

OK, I’m not an expert, but it looks to me like a problem reading the SD card, which is fairly common. It could be a bad or slightly incompatible card, so if you have choices, particularly a different brand I think that would be worth trying.

If you haven’t dis-assembled yet, I would look at the card first.

I have had good results with SanDisk 32GB (Pack of 2) Ultra microSDHC UHS-I Memory Card (2x32GB) with Adapter - SDSQUA4-032G-GN6MT:

If changing the SD card doesn’t work, you could try re-plugging the ‘extension’ cable that goes from the Pi to the external socket for the SD card. You can also eliminate the cable by plugging the SD card directly into the Pi, just for troubleshooting purposes.

I wouldn’t bother about the inverted display till this problem is found-corrected, it most likely will be fixed also by resolving the I/O problem and getting a successful startup.

Don’t give up, Zynthian is worth the trouble once you get past these problems.

Someone else may supply more specific help as well - I wonder if others have seen the ‘interrupt while no I/O is in progress’ before?

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Hi @banjo !

It really seems a problem with the SD-card.
As i explained before, the display is physically mounted inverted and the software takes care of rotating it, so it’s normal to see everything up-side-down when something goes wrong and the system can’t boot properly.
I would try a different SD-card. I use Sandisk Ultra and Sandisk Extreme 32/64GB with very good results. Verify that the SD-image has has been downloaded completely and it’s correct. You can use the check-sum file from the download page.


It this doesn’t work, verify that the SD-adaptor is correctly plugged in the mainboard and RBPi. You could try to plug the SD-card directly in the RBPi to see if there is a problems with this cable.

Anyway, don’t be worried, because you will get your zynthian working for sure. All the main boards have been checked by us before shipping, but not the RBPi. that it’s brand-new. At the end, if something is broken, we will send you a replacement ASAP.

This gives you extra-powers for solving this issue :wink:

Good luck!


Thank you for your advice,
writing to higher quality sd card
seems to have done the trick.

glad i didn’t try reassembly

FYI, i play a synth guitar
and do this music…


Far out!