<< Solved >> The partition map needs to be repaired because there's a problem with EFI system partition's file system.

[Jithin.C.V]

@Jithin.C.V

when trying to make the disk mount read-write I was trying different commands to mount the volume
but in both ways to mounting an efi partition the results are the same. Probably the r stands for ReadOnly?

iMac:~ raj$ sudo mkdir /Volumes/efi
Password:
iMac:~ raj$ sudo mount -rw -t msdos /dev/disk5s1 /Volumes/efi
iMac:~ raj$ sudo fsck_msdos /dev/disk5s1
** /dev/rdisk5s1 (NO WRITE)
** Phase 1 - Preparing FAT
** Phase 2 - Checking Directories
** Phase 3 - Checking for Orphan Clusters
Found orphan cluster(s)
Fix? no
Found 37226 orphaned clusters
1085 files, 80944 KiB free (161889 clusters)

also the same with

iMac:~ raj$ sudo diskutil mount /dev/disk5s1
Volume EFI on /dev/disk5s1 mounted
iMac:~ raj$ sudo fsck_msdos /dev/disk5s1
** /dev/rdisk5s1 (NO WRITE)
** Phase 1 - Preparing FAT
** Phase 2 - Checking Directories
** Phase 3 - Checking for Orphan Clusters
Found orphan cluster(s)
Fix? no
Found 37226 orphaned clusters
1072 files, 80987 KiB free (161974 clusters)

If you have no data in the drive, please do recreation of partition map.

sudo diskutil eraseDisk JHFS+ "MY DRIVE" disk5

Note:- Above command will wipe out everything from the hard disk/SSD. Make sure you have taken backup of important data if any are there.

If you want to fix the Orphan Cluster detetected, please try below command:-

sudo fsck_msdos -y /dev/disk5s1

If any of the above fixing the issue, then you are lucky. Else please plan for a replacement of HDD/SSD.


Regarding your question on r:-

sudo mount -rw -t msdos /dev/disk5s1 /Volumes/efi

r - Stand for Read
w - Stands for Write.

Both are the Unix/Linux mount options on a file system. Simple mount -t msdos /dev/disk5s1 /Volumes/efi is enough to get read/write access on EFI. It is not mandatory to use -rw flag.

 

[theSov]

I used the following to fix the problem:
sudo fsck_msdos disk0s1

Good deal, thanks for sharing the solution. Worked for me as well.