Error with SM-G361F system.img

[Max1Truc]

Hello @anestisb ,

I've got a system.img from the official ROM G361FXXU1APB1 of Samsung Galaxy SM-G361F.

(Download here)

The problem is, if I "repack" this image, the newly-created image (packed in a tarfile) is accepted by Odin but rejected by the device.

EDIT:
It seems that the size of the input chunks is 2562 in the original system.img, but,
because 2562 % 4 != 0, img2simg is rejecting my command to force the use of
2562-sized blocks `img2simg system.raw.img system.img 2562`

I am showing a case were I didn't modify the filesystem from simg2img before converting it back with img2simg for clarification.

I am "repacking" this way:

root@pc:~/Desktop# simg2img system.img system.raw.img
root@pc:~/Desktop# mv system.img system.original.img
root@pc:~/Desktop# img2simg system.raw.img system.img
root@pc:~/Desktop# tar cvf G361FXXU1APB1.tar system.img
root@pc:~/Desktop# md5sum -t G361FXXU1APB1.tar >> G361FXXU1APB1.tar
root@pc:~/Desktop# mv G361FXXU1APB1.tar G361FXXU1APB1.tar.md5

Additional information :

• Repacking with neither simg2img nor img2simg works with Odin and is accepted by the device:

root@pc:~/Desktop# tar cvf G361FXXU1APB1.tar system.img
root@pc:~/Desktop# md5sum -t G361FXXU1APB1.tar >> G361FXXU1APB1.tar
root@pc:~/Desktop# mv G361FXXU1APB1.tar G361FXXU1APB1.tar.md5

• I'm using a Linux VM inside of Windows 10
• About the base image :

root@pc:~/Desktop# file system.img 
system.img: Android sparse image, version: 1.0, Total of 471808 4096-byte output blocks in 2562 input chunks. 

root@pc:~/Desktop# python2 ./android-simg2img/simg_dump.py system.img
simg_dump.py: system.img: The file header size was expected to be 28, but is 32.

• About the generated image :

root@pc:~/Desktop# file system.img
system.img: Android sparse image, version: 1.0, Total of 471808 4096-byte output blocks in 1692 input chunks.

root@pc:~/Desktop# python2 ./android-simg2img/simg_dump.py system.img 
system.img: Total of 471808 4096-byte output blocks in 1692 input chunks.

• About the raw image :

root@pc:~/Desktop# file system.raw.img
system.raw.img: Linux rev 1.0 ext4 filesystem data, UUID=57f8f4bc-abf4-655f-bf67-946fc0f9f25b (extents) (large files)

[Max1Truc]

Self-answer for guys looking at the solution... You have to post-process the "repacked" system.img with this tool from chainfire, before flashing it on the phone.