TerryG
Posts: 9
Joined: Sun Jun 21, 2015 3:06 pm

Strange colourful shapes whilst booting.

Sun Jun 21, 2015 5:18 pm

Hi everyone - first time here so hoping someone can help me out.

I have a RPi2 with SanDisk 8GB Class 10 SD card.

I managed to write the Win10 IoT flash.ffu image no problem. However, when fitted to the RPi2 and powered on, all I get are some strange colourful changing shapes. From the response of the RPi LEDS and what's on the screen, it seems like the RPi is doing something and it reboots. Eventually it stops. It seems like its displaying text but its totally fuzzy and unreadable.

As this is a brand new Pi and SD card, I reformatted the SD Card with Raspian and it worked perfectly.
I put Win10 back on and still the same colourful changing shapes.

What's interesting is that when I put the SD card into a PC, it says there's only 64MB.
I have run some tests on the SD Card and its got approx 8GB and runs well over 10MB/s so it seems good

Anyone experienced this and more to the point, got it to work?

Regards
Terry

haroldpulcher
Posts: 58
Joined: Tue Jun 09, 2015 8:08 pm
Contact: Website

Re: Strange colourful shapes whilst booting.

Mon Jun 22, 2015 6:31 pm

I do know that the graphics drivers are currently "under development". I see some weirdness at boot as well.

What is the resolution of the monitor?

Harold

markrad_msft
Posts: 58
Joined: Thu May 07, 2015 7:46 pm

Re: Strange colourful shapes whilst booting.

Tue Jun 23, 2015 12:40 am

Make sure that you have a good power supply for the RPi2. Lower quality power supplies can cause a myriad of issues including random reboots.
Mark Radbourne | Microsoft | Windows 10 IoT Core Insider Preview Support | This posting is provided 'as is' with no warranties and confers no rights.

TerryG
Posts: 9
Joined: Sun Jun 21, 2015 3:06 pm

Re: Strange colourful shapes whilst booting.

Tue Jun 23, 2015 7:56 am

Harold

Its an LG 19MN43D with pixel resolution 1366 x 768

Mark

The Pi worked perfectly with Raspian with the PSU I've got

Regards
Terry

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DougieLawson
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Re: Strange colourful shapes whilst booting.

Tue Jun 23, 2015 8:59 am

You need to add

Code: Select all

hdmi_group=2
hdmi_mode=81
to the config.txt that you'll find on partition #1 on your WinIoT SDCard.
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TerryG
Posts: 9
Joined: Sun Jun 21, 2015 3:06 pm

Re: Strange colourful shapes whilst booting.

Tue Jun 23, 2015 8:23 pm

Hi Dougie

I tried your suggestion but no joy.

I found one of your posts at https://www.raspberrypi.org/forums/viewtopic.php?f=105&t=109129
so I tried hdmi_group=2, hdmi_mode=4 instead.

Have now got something legible on the screen though a lot of the right hand side is offscreen or wrapped around.

Tried hdmi_mode=86 (HDMI_DMT_1366x768_RB = 0x56, /**<1366x768 reduced blanking */) but that didn't work either.

Will have to try some other settings to get it rght

Cheers
Terr

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DougieLawson
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Re: Strange colourful shapes whilst booting.

Tue Jun 23, 2015 8:31 pm

If you can boot an alternative Raspbian SDCard you can take a look at it with the tvservice -m DMT command and see what modes the GPU supports with your TV/Monitor. You can then try something better than 640 with WinIoT.

Perhaps we should encourage Microsoft to port the tvservice command (http://github.com/raspberrypi/userland has the source code) to run on the WinIoT system so we can look at settings and tweak the config without needing to boot Linux.
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TerryG
Posts: 9
Joined: Sun Jun 21, 2015 3:06 pm

Re: Strange colourful shapes whilst booting.

Wed Jun 24, 2015 7:51 am

Thanks Dougie I'll give it a try

Terry

Josiah_B
Posts: 15
Joined: Thu Jun 25, 2015 8:12 pm

Re: Strange colourful shapes whilst booting.

Thu Jun 25, 2015 8:21 pm

Hey,
I had the same issue.
My fix was to add these 2 lines to the "config.txt" file:
hdmi_group=2 # forces DVI timing to be used
hdmi_mode=0x27 # set the mode to 1360x768

It leaves a few pixels (6 actually) at the bottom of the screen black, but its the closest I could get.

EDIT:
I should probably add links to my references, so here they are:
https://en.wikipedia.org/wiki/List_of_c ... esolutions
viewtopic.php?t=5851

I used the first one to find a resolution with the same or similar aspect ratio.
The second one is where I got the hdmi_mode number from.

TerryG
Posts: 9
Joined: Sun Jun 21, 2015 3:06 pm

Re: Strange colourful shapes whilst booting.

Fri Jun 26, 2015 5:38 pm

Hi Josiah

That seems to have done it - now looking pretty good. Thanks for the info

Just to recap for anyone making their way thru this series of posts

For LG 19MN43D with pixel resolution 1366 x 768 getting strange colourful shapes at boot and totally illegible to read
Add the following to config.txt (on the SD Card)

hdmi_group=2 # forces DVI timing to be used
hdmi_mode=0x27 # set the mode to 1360x768

Regards
Terry

Josiah_B
Posts: 15
Joined: Thu Jun 25, 2015 8:12 pm

Re: Strange colourful shapes whilst booting.

Fri Jun 26, 2015 6:34 pm

Glad to hear that you got it working.
TerryG wrote: Just to recap for anyone making their way thru this series of posts

For LG 19MN43D with pixel resolution 1366 x 768 getting strange colourful shapes at boot and totally illegible to read
Add the following to config.txt (on the SD Card)

hdmi_group=2 # forces DVI timing to be used
hdmi_mode=0x27 # set the mode to 1360x768
I also want to add:
You can add those 2 lines to the "config.txt" file before the first boot. And I don't think its display specific, but rather a case of the IoT Core not liking the 1366 x 768 res.

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