After struggling during 3 days to install the KDE edition into an old laptop with only Legacy (non UEFI) option, and after multiple reboot faillure (system not found) when trying to boot following an apparently installation, I have found a solution working for me… so maybe also for others.
Just want to share it…
After installing, I boot with a GParted USB and saw that Calamares did not flagged any partition as boot. I first re-installed and flagged the Ext4 first (and main) partition build by Calamares. It did not help.
So I did the following: I installed another distro (nevermind the name) which uses another installer, and I could boot without issue. Then I rebooted with the Manjaro installer and manually installed Manjaro while reformating but keeping the partitions builded by the other distro. AND IT WORKED.
The whole schema is as following :
SDA1: Ext4, flag as Boot - 255 Mb
SDA2: Ext4, flag as Root - the rest of my HD apart the Swap
SDA5: Swap (inside Extended) - 3.2 Gb
I add a screenshot of the partitions below
I believe others schemas would work also, but this is definitively a working solution for me with Legacy bios.