How to recover packages downgraded by aptitude?

Question

I am installing fsl.

In a brandnew vps with Debian10, the command works perfectly.

wget -O- http://neuro.debian.net/lists/buster.au.full | sudo tee /etc/apt/sources.list.d/neurodebian.sources.list
sudo apt-key adv --recv-keys --keyserver hkp://pool.sks-keyservers.net:80 0xA5D32F012649A5A9
sudo apt-get update
sudo apt-get install fsl-core

However, when I try to install it on my own computer(exactly the same version of Debian10), it says

The following packages have unmet dependencies:
fsl-5.0-core : Depends: libnifti2 but it is not installable
                Recommends: fsl-5.0-eddy-nonfree but it is not installable
                Recommends: fslview but it is not installable
E: Unable to correct problems, you have held broken packages.

I recall that when I install fail2ban a month ago, I used aptitude instead of apt-get, aptitude suggeests to downgrade some packages, I followed that. I suspect the unmet dependencies is related to those downgraded packages. Since I only install a few softwares on my computer, including debian-desktop, vncserver, two anti-virus software, and fail2ban. Except fail2ban, the others were installed by apt-get.

However, after removing fail2ban, I still can not install fsl. I use aptitude to find out the details

sudo aptitude install fsl-core

it says

The following packages have unmet dependencies:
 libnifticdf2 : Breaks: libnifti2 (<= 3.0) but 2.0.0+git186-g84740c2-1 is to be installed
 libniftiio2 : Breaks: libnifti2 (<= 3.0) but 2.0.0+git186-g84740c2-1 is to be installed

By the way, the error message is confusing, it requires libnifti2<=3.0, and the to-be-installed is 2.0, apprently the requirement is satisfied. I don't why this would break the dependency.

Is there any way that I can revert the downgraded packages caused by aptitude?

Answer 1

Such version skew is probably due to a seriously outdated package from some third party (not an official package for your distribution). See if the base software and the package are still being actively maintained (perhaps by other people, or moved to some other venue, like from Sourceforge to Github); if none of the above, make sure you have the meaning of "you are completely on your own" clear. Look for alternatives.

Check the dependencies (note there can be indirect ones!).

Try to contact the packager, who is most probably not the person who wrote the program in the first place. Perhaps there are people in charge of the package in your distribution.

Get the source package, grab a copy of the latest upstream source, and make your own package (note that there might be distribution specific patches -- e.g., for stuff like configuration file placement or naming--, bugs that since have been fixed upstream - or not, and so on; all that may require a bit of sorting out/porting effort).