When everthing is installed apart from Grub,
then you must install grub.
Use the Manjaro USB stick, boot from it, chroot into the system and then:
sudo grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=manjaro --recheck
sudo grub-mkconfig -o /boot/grub/grub.cfg
You mean restart or stay after the bootloader fails? I’m not that familiar with chroot. Sry.
Boot from the Manjaro USB stick, manjaro-chroot --a on console and then execute the commands above.
Hello @Tzalim 
When installing Manjaro on BTRFS, then root is normally at /@/ and /home at /@home/ as subvolumes. Roughly saying it is working like a partition; you can mount a subvolume like a partition.
So when mounting btrfs it must be like that:
sudo mount -o subvol=@ /dev/sda2 /mnt
sudo mount -o subvol=@home /dev/sda2 /mnt/home
sudo mount /dev/sda1 /mnt/boot/efi
Then chroot with the manjaro-helper script:
manjaro-chroot /mnt /bin/bash
However there is also a great article on the wiki: GRUB/Restore the GRUB Bootloader - Manjaro
I rebooted, went back in the installer, did what I always do which is delete the drive and left the defaults like swap and ext4 and didn’t choose btrfs. I’m used to ext4, I just thought btrfs was quicker and better and Garuda uses it.
Ok, so I did what you said but it couldn’t find manjaro-chroot --a so I just did manjaro-chroot -a
[manjaro@manjaro-cinnamon ~]$ manjaro-chroot -a
grub-probe: error: cannot find a GRUB drive for /dev/sdb1. Check your device.map.
grub-probe: error: cannot find a GRUB drive for /dev/sdb1. Check your device.map.
==> Mounting (ManjaroLinux) [/dev/sda2]
--> mount: [/mnt]
--> mount: [/mnt/boot/efi]
[root@manjaro-cinnamon /]# sudo grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=manjaro --recheck
Installing for x86_64-efi platform.
Could not prepare Boot variable: No space left on device
grub-install: error: efibootmgr failed to register the boot entry: Input/output error.
[root@manjaro-cinnamon /]# sudo grub-mkconfig -o /boot/grub/grub.cfg
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-5.13-x86_64
Found initrd image: /boot/intel-ucode.img /boot/amd-ucode.img /boot/initramfs-5.13-x86_64.img
Found initrd fallback image: /boot/initramfs-5.13-x86_64-fallback.img
Warning: os-prober will be executed to detect other bootable partitions.
Its output will be used to detect bootable binaries on them and create new boot entries.
grub-probe: error: cannot find a GRUB drive for /dev/sdb1. Check your device.map.
grub-probe: error: cannot find a GRUB drive for /dev/sdb1. Check your device.map.
Adding boot menu entry for UEFI Firmware Settings ...
Found memtest86+ image: /boot/memtest86+/memtest.bin
done
And that all… I rebooted and still no bootable device found. So, I went back into the live usb and that’s where I am now.
Could you check if the partition is full? Reformat it and try again?
Looks like, it cannot register an entry…
I restarted and went back into the installer and tried again and when it got to the partitions part I said to erase the disk and I left the defaults like it was with no swap and ext4. But I will try again and see if there is anything different. But I just did it, so there shouldn’t be.
Ok, now what my partition tab says when I’m getting ready to install, like the summary is what I have in the image below.
I’m about to do an install.
Edit: The reason I have all unallocated space is I did a fresh drive with gparted. I know I tried that before with my friend that was helping me.
you have to ckeck option UEFI motherboard before
I haven’t had secure boot enabled for years (about 5 yrs or so sense getting this laptop), ever sense I was on windows 10, it’s been disabled. I don’t have CSM. I have UEFI enabled, legacy disabled. And no other boot options that is in that link. I will post the commands that you referenced.
[manjaro@manjaro-cinnamon ~]$ inxi
CPU: Quad Core AMD A8-7410 APU with AMD Radeon R5 Graphics (-MCP-)
speed/min/max: 1094/1000/2200 MHz Kernel: 5.13.13-1-MANJARO x86_64
Up: 8h 53m Mem: 1492.3/6899.5 MiB (21.6%) Storage: 945.83 GiB (0.7% used)
Procs: 213 Shell: Bash inxi: 3.3.06
[manjaro@manjaro-cinnamon ~]$ test -d /sys/firmware/efi && echo efi || echo bios
efi
[manjaro@manjaro-cinnamon ~]$ sudo efibootmgr -v
BootCurrent: 0002
Timeout: 0 seconds
BootOrder: 2001,2002,2003
Boot0000* Notebook Hard Drive - WDC WD10JPVX-60JC3T0 BBS(HD,,0x500)................-...........A.....................................}.........A.......................
Boot0001* USB Hard Drive - USB BBS(7,,0x500)..................................................................vH........A...........................
Boot0002* USB Hard Drive (UEFI) - USB PciRoot(0x0)/Pci(0x12,0x0)/USB(0,0)/USB(1,0)/HD(1,MBR,0x0,0x5c2cd4,0x2000)RC
Boot2001* USB Drive (UEFI) RC
Boot2002* Internal CD/DVD ROM Drive (UEFI) RC
Boot3000* Internal Hard Disk or Solid State Disk RC
Boot3001* Internal Hard Disk or Solid State Disk RC
Boot3002* Internal Hard Disk or Solid State Disk RC
Boot3003* Internal Hard Disk or Solid State Disk RC
Boot3004* Internal Hard Disk or Solid State Disk RC
[manjaro@manjaro-cinnamon ~]$ sudo parted -l
Model: ATA WDC WD10JPVX-60J (scsi)
Disk /dev/sda: 1000GB
Sector size (logical/physical): 512B/4096B
Partition Table: gpt
Disk Flags:
Number Start End Size File system Name Flags
1 2097kB 317MB 315MB fat32 boot, esp
2 317MB 1000GB 1000GB ext4 root
Model: USB SanDisk 3.2Gen1 (scsi)
Disk /dev/sdb: 15.4GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Disk Flags:
Number Start End Size Type File system Flags
2 3093MB 3097MB 4194kB primary esp
[manjaro@manjaro-cinnamon ~]$ sudo lsblk -fs
NAME FSTYPE FSVER LABEL UUID FSAVAIL FSUSE% MOUNTPOINTS
loop0
squash 4.0 0 100% /run/miso/sfs/livefs
loop1
squash 4.0 0 100% /run/miso/sfs/mhwdfs
loop2
squash 4.0 0 100% /run/miso/sfs/desktopfs
loop3
squash 4.0 0 100% /run/miso/sfs/rootfs
sda1 vfat FAT32 NO_LABEL
│ 266C-8298 299.2M 0% /tmp/calamares-root-t5ty9044/boot/efi
└─sda
sda2 ext4 1.0 47982c44-559c-4bde-9856-85ad2ea58a08 862.2G 1% /tmp/calamares-root-t5ty9044
└─sda
sdb1 iso966 Jolie MANJARO_CINNAMON_2112
│ 2021-09-07-17-04-26-00
└─sdb
iso966 Jolie MANJARO_CINNAMON_2112
2021-09-07-17-04-26-00 0 100% /run/miso/bootmnt
sdb2 vfat FAT12 MISO_EFI
│ 5D2E-5B66
└─sdb
iso966 Jolie MANJARO_CINNAMON_2112
2021-09-07-17-04-26-00 0 100% /run/miso/bootmnt
sr0
So the problem is clearly between efibootmgr and your UEFI.
What makes me think are these entries:
It could be possible that your UEFI NVRAM has no space left for new entries… You can delete unnecessary entries with:
sudo efibootmgr --delete-bootnum --bootnum 3000
It say’s I have to specify an entry to delete but did do the -b option but its just like a help for the different options. I did all of the entries and it told me the same thing. Like 3001, 3002, 3003 and 3004.
[manjaro@manjaro-cinnamon ~]$ sudo efibootmgr --delete-bootnum 3000
You must specify an entry to delete (see the -b option).
If you want to remove entry Boot3000 try
sudo efibootmgr -b 3000 -B
I did them all except Boot3004, should I do that one as well? And then restart and do the installation again?
[manjaro@manjaro-cinnamon ~]$ sudo efibootmgr
BootCurrent: 0002
Timeout: 0 seconds
BootOrder: 2001,2002,2003
Boot0000* Notebook Hard Drive - WDC WD10JPVX-60JC3T0
Boot0001* USB Hard Drive - USB
Boot0002* USB Hard Drive (UEFI) - USB
Boot2001* USB Drive (UEFI)
Boot2002* Internal CD/DVD ROM Drive (UEFI)
Boot3004* Internal Hard Disk or Solid State Disk
Thanks @Wollie I always forget about the --boot-num parameter xD Corrected… 
I would first suggest to re-run the grub-install procedure, like done before:
Ok, idk what to do next. I put in these commands…
[manjaro@manjaro-cinnamon ~]$ manjaro-chroot -a
grub-probe: error: cannot find a GRUB drive for /dev/sdb1. Check your device.map.
grub-probe: error: cannot find a GRUB drive for /dev/sdb1. Check your device.map.
==> Mounting (ManjaroLinux) [/dev/sda2]
--> mount: [/mnt]
--> mount: [/mnt/boot/efi]
and then…
[root@manjaro-cinnamon /]# sudo grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=manjaro --recheck
Installing for x86_64-efi platform.
Could not prepare Boot variable: No space left on device
grub-install: error: efibootmgr failed to register the boot entry: Input/output error.
[root@manjaro-cinnamon /]# sudo grub-mkconfig -o /boot/grub/grub.cfg
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-5.13-x86_64
Found initrd image: /boot/intel-ucode.img /boot/amd-ucode.img /boot/initramfs-5.13-x86_64.img
Found initrd fallback image: /boot/initramfs-5.13-x86_64-fallback.img
Warning: os-prober will be executed to detect other bootable partitions.
Its output will be used to detect bootable binaries on them and create new boot entries.
grub-probe: error: cannot find a GRUB drive for /dev/sdb1. Check your device.map.
grub-probe: error: cannot find a GRUB drive for /dev/sdb1. Check your device.map.
Adding boot menu entry for UEFI Firmware Settings ...
Found memtest86+ image: /boot/memtest86+/memtest.bin
done
I haven’t restarted yet.
can you check if there is enough size for /boot/efi ?
sudo df -ThFilesystem Type Size Used Avail Use% Mounted on
dev devtmpfs 3.4G 0 3.4G 0% /dev
run tmpfs 3.4G 114M 3.3G 4% /run
/dev/sdb iso9660 2.9G 2.9G 0 100% /run/miso/bootmnt
cowspace tmpfs 256M 0 256M 0% /run/miso/cowspace
overlay_root tmpfs 5.1G 193M 4.9G 4% /run/miso/overlay_root
/dev/loop0 squashfs 56M 56M 0 100% /run/miso/sfs/livefs
/dev/loop1 squashfs 787M 787M 0 100% /run/miso/sfs/mhwdfs
/dev/loop2 squashfs 1.4G 1.4G 0 100% /run/miso/sfs/desktopfs
/dev/loop3 squashfs 694M 694M 0 100% /run/miso/sfs/rootfs
overlay overlay 5.1G 193M 4.9G 4% /
tmpfs tmpfs 3.4G 61M 3.4G 2% /dev/shm
tmpfs tmpfs 3.4G 56M 3.4G 2% /tmp
tmpfs tmpfs 3.4G 2.4M 3.4G 1% /etc/pacman.d/gnupg
tmpfs tmpfs 690M 124K 690M 1% /run/user/1000
/dev/sda2 ext4 916G 6.8G 863G 1% /mnt
/dev/sda1 vfat 300M 148K 300M 1% /mnt/boot/efi
tmpfs tmpfs 3.4G 0 3.4G 0% /tmp/calamares-root-t5ty9044/run
shm tmpfs 3.4G 0 3.4G 0% /mnt/dev/shm
run tmpfs 3.4G 8.0K 3.4G 1% /mnt/run
tmp tmpfs 3.4G 0 3.4G 0% /mnt/tmp
overlay overlay 5.1G 193M 4.9G 4% /mnt/etc/resolv.conf
can you from chroot
return
sudo manjaro -chroot -a
cat /etc/fstab
inxi -Mxa
efivar -l
cat /sys/firmware/efi/efivars/dump-*
exit (end-chroot)you may need to mount efivar if efivar -l is not ok before command grub-install
mount -t efivarfs efivarfs /sys/firmware/efi/efivars
or
remove dump
if efivar is ok and no dump , add this line command kernel on boot ( live iso )
efi_no_storage_paranoia and after chroot
recheck state efivar and dump files
before grub-install