I installed it from the Calamaries Installer found in the LIVE USB ISO this time. And Instead of my primary hdd, I installed it on the other one. Works now, thanks for all of your support, dear nerds.
This is the screen a few seconds afterwards
Absolutely not an expert or anything, but is it possible that the partition of your harddrive that you’re trying to install Debian on (hd0) is too small?
The original error actually makes it sound like there’s a partition on hda that’s bigger than hda itself.
Considering that it has a 2020 firmware, and is built by “to be filled by OEM”, my completely unfounded wild guess is that the system firmware has broken legacy boot support. From other posts here, I gather you’re using a legacy dos-style partition table. Try installing again with GPT/EFI instead.