[Solved] Debian Installer Screen Garbled

[debuster]

I got a PC with AMD 5600G. I don't have any external monitor, so using HDMI cable to connect to TV. I was thinking of converting it into a sort of server, hence non GUI, minimal system needed.

When trying to install debian, my installer screen becomes garbled. On both Graphical and normal installer.

(P.S: The image does not belong to me, But my screen situation is almost same...)
Searching on internet shows the issue is nothing new, but i did not find actual solution that works. Tried setting gfxmode (default was correct for me though), rebooting....

I'm on venoty. But I also tried on barebone and had the same result. I also tried on Normal and grub mode. No luck.

Booting into Debian Live works, but i dont know how can i install a minimal system, only GUI from a live installer.

[mrmazda]

Just as on normal installations, the screen resolution for vttys and text mode installer can be configured on the installer's linu line. Simply append such mode as an option via video=, such as video=1280x720@60, which all widescreen TVs should fully support. Cheaper HD TV panels are typically only 1366x768 or 1360x768, yet support 1280x720, which is 720p, as well as 1920x1080, which is 1080i. It could be you have one of these that the installer is misinterpreting as supporting 1920x1080p that the TV can't actually handle.

Some TVs have an HDMI port labeled differently from the other(s), intended for use by PCs, to which description is attached "DVI". If yours has this, try it.

Does this TV work normally as a TV? What age/model/brand is it?

[Dude Guyman]

I had the same problem. Info/solution here: viewtopic.php?t=155182

Hope that squares it away for you too.

[debuster]

Does this TV work normally as a TV? What age/model/brand is it?

TV: `Sony KLV-40R552C`. Tried both HDMI ports. No luck

Just as on normal installations, the screen resolution for vttys and text mode installer can be configured on the installer's linu line. Simply append such mode as an option via video=, such as video=1280x720@60

Can you please break it down how to get to said linu line? (I'm using ventoy.) Also, not sure if changing screen resolution would fix it. Following one suggestion i found, i checked gfxmode from the installer menu (grub command). My TV is 1920x1080 and the deafult was same. I still manually set it to 1920x1080. It didnt work...

[debuster]

I had the same problem. Info/solution here: viewtopic.php?t=155182

Hope that squares it away for you too.

I think I'm on UEFI . Did you came accross anything helpful while trying to solve your problem?

[debuster]

Update: Suggested related post sent me for further searching and seemed like it shouldn't be happening for a UEFI installation. So, checked my bios and found CSM was enabled (It bridges legacy with uefi). disabling it solved the issue.

[mrmazda]

Just as on normal installations, the screen resolution for vttys and text mode installer can be configured on the installer's linu line. Simply append such mode as an option via video=, such as video=1280x720@60

Can you please break it down how to get to said linu line? (I'm using ventoy.) Also, not sure if changing screen resolution would fix it. Following one suggestion i found, i checked gfxmode from the installer menu (grub command). My TV is 1920x1080 and the deafult was same. I still manually set it to 1920x1080. It didnt work...

On the boot menu screen that follows applying your Ventoy menu selection, strike the E key to put the boot menu in edit mode. Navigate to the end of the linu line, which usually wraps, then append.

As you wrote TV, I assumed that yours, as many do, might be supporting 1920x1080 via emulation. A lesser mode than native stands a chance of working when support for the highest/native mode fails. If you're not sure whether yours supports 1920x1080 directly, run xrandr to find out.

Nice to know that disabling CSM was all you needed! Having it enabled during installation causes a frustrating amount of post-installation help requests, along with others like your own.