How to upgrade Debian 9 Stretch to Debian 10 Buster -

This article explains a system upgrade procedure from Debian 9 Stretch to Debian 10 Buster. Currently, Debian Buster is in a state of testing. The stable Debian 10 Buster release date is to be expected in a second or third quarter of 2019.
This is a companion discussion topic for the original entry at


You suggestions worked. Managed to upgrade from debian 9 to buster10 on my laptop.


Followed the steps without errors on a Thinkpad T400. When booting I’m getting a black screen that flashes every 2 secs and the cursor is somewhat visible but can’t be moved.
Recovery mode Debian 8/3.16 kernel works.
Is there a way to go back to Stretch?
Thank you.

Robert K -> frogger

Perhaps you’re using a proprietary Nvidia driver and it isn’t being upgraded properly? I’m worried that will happen to me, and taking precautions in advance.

frogger -> Robert K

Switchable Intel GMA 4500MHD and ATI Mobility Radeon HD 3470 video cards. Flashing blackscreen with both. IIRC the default video driver was installed in Stretch.


Thank you. So far it’s working.

When I type in the command:
sed -i ‘s/stretch/buster/g’ /etc/apt/sources.list
I get response:
sed: couldn’t open temporary file /etc/apt/sedxSgci2: Permission denied
I think this is because a noexec flag was placed on it. Do you know any way to bypass this?

Run the command as root ( # ) user. First change to root:
$ su
and then execute the command:
# sed -i ‘s/stretch/buster/g’ /etc/apt/sources.list

It’s asking for a password. What do I do?

enter root ( administrative ) password.

If it does not help create a new thread on this forum a describe your issue. thanks

Never mind I got in, but now it says:
sed: -e expression #1, char 1: unknown command: `�’

Good doc, thanks…
This strategy is the good one for every “Debian” upgrade. I have just a recommendation:
disable every externals non pure debian repositories before upgrade.

Some websites and word processing applications convert straight quotes to curly quotes, I suspect this is the cause to your issue. Use a search engine for more insight into the cause and effect.