Hello. I am new to linux and am fascinated by the ideology behind Manjaro and how it works. So I decided to switch from Windows 10 and downloaded the Manjaro 21.0.5 KDE iso in order to dual boot.
In my 1 TB HDD (GPT) inside HP 245 G7 Laptop with i3 6006U, I made a partition of 350 GB at the end of the disk. Then I booted the live USB and installed Manjaro (Partition 1: 512 MB, fat32, /boot/efi. flag: boot. Partition 2: 349.5 GB, ext4, /). Manjaro installed successfully.
But when I rebooted, no efi entry, no grub, only windows 
. I booted again from the USB, ran lsblk, both partitions were there. Tried to recover grub through manjaro-chroot. installed grub successfully, efibootmgr showed Manjaro entry; but after reboot back to level 0 
. Thought the iso might be damaged, so downloaded the iso again, but no result. Then I began to suspect Calamares, so tried installing KDE Neon, but it installed successfully and the booted successfully. But I wanna use Manjaro! Please help.
Hi @Archenth2001,
Welcome to the forum, the first think you need to is read the Manjaro Guide in order to install it properly. You are also not the first one who make in troubles trying to install Manjaro. For example, read this post in order to see whether you follow the installation guide.
‘Questions about dual booting Windows after installing Manjaro’
The other problem could be related to this post:
‘Os-prober, and grub can't find windows 10’
Hope this help, regards
Thanks a lot for being so helpful 
. I actually found out a kind-of solution. It turns out to be the efi partition was getting the flag legacy boot instead of boot. Booting from a live iso, I changed the flag in gparted, booted from the efi partition. Problem solved. 
(Regarding the second line, I installed manjaro twice, and both times saw that flag issue, though I am not sure what the reason was, as I am damn sure I checked the boot flag 
)