run fix_eoi.py -h for usage. Added (recursive) folder search + overwrite functionality. Tested with S9+ and Python 3.7.9

fix_eoi.py

#!/usr/bin/python

#fixes Samsung's broken Panorama jpgs by adding EOI markers at the end of the file

#positional arguments:
#  path                 file or folderpath

#optional arguments:
#  -h, --help           show this help message and exit
#  -d, --dump           dumps Samsung specific data that is added to the image
#  -R, -r, --recursive
#  -o, --overwrite      overwrite orginial file
#  -f, --force          do not create a backup of the original panorama


# The Samsung trailer format is based on the implementation from ExifTool
# http://www.sno.phy.queensu.ca/~phil/exiftool/

# Forked from https://gist.github.com/HikerBoricua/ who forked it from https://gist.github.com/bcyrill 
# Backwards compatible to @HikerBoricua version except the dump argument is now -d flag
# Meant to be run from a batch like the Windows CMD one in the block comment below
"""
echo off
python fix_eoi.py "./"
echo If everything OK, press any key to delete all *_orig.jpg files
set /p answer="Otherwise close this window to prevent loss of originals ..."
del *_orig.jpg
echo on
"""

import mmap
import struct
import os
import sys
import shutil
import argparse

def addEOF(files):
	for file_fullname in files:
		(file_name, file_ext) = os.path.splitext(file_fullname)
		file_basename = os.path.basename(file_fullname)

		with open(file_fullname, 'r+b') as fh:
			m = mmap.mmap(fh.fileno(), 0, access=mmap.ACCESS_READ)
			b = bytearray(m)
			
			trailer_tail = b[-4:]
			
			if trailer_tail != bytearray(b'SEFT'):
				print('{}: Expected Samsung (b\'SEFT\') trailer but found {}'.format(file_basename, trailer_tail))
				continue
			# else:
				# print("Found SEFT")
			
			length = struct.unpack_from("<I",b[-8:-4])[0]	
			trailer = b[-(8+length):]
			
			endPos = len(b)
			dirPos = endPos-(8+length)
			
			if trailer[0:4] != bytearray(b'SEFH'):
				print('{}: Expected Samsung (b\'SEFH\') trailer but found {}'.format(file_basename, trailer[0:4]))
				continue
			# else:
				# print("Found SEFH")
			
			version = struct.unpack_from("<I",trailer[4:8])[0]
			if version not in set([101, 103, 105, 106]):
				print('{}: Expected Samsung trailer version in [101,103,105,106] but found {}'.format(file_basename, version))
				continue
			
			count = struct.unpack_from("<I",trailer[8:12])[0]
			
			firstBlock = 0
			is_pano = 0
			
			for index in range(0, count):
				entry = 12 + 12 * index;
				
				type = struct.unpack_from("<H",trailer[entry+2:entry+4])[0]
				noff = struct.unpack_from("<I",trailer[entry+4:entry+8])[0]
				size = struct.unpack_from("<I",trailer[entry+8:entry+12])[0]
				
				if firstBlock < noff:
					firstBlock = noff
				
				entryPos = dirPos - noff
				entryLen = size
				
				data = b[entryPos:entryPos+entryLen]
				
				# Validate as the type has to match the SEFH/SEFT entry type
				entry_type = struct.unpack_from("<H",data[2:4])[0]
				if type != entry_type:
					print(file_basename + ': Block type '+ type + ' doesn\'t match entry type ' + entry_type)
					continue
					
				entry_offset = struct.unpack_from("<I",data[4:8])[0]
				entry_name = data[8:8+entry_offset].decode("utf-8") 
				
				if entry_name == "Panorama_Shot_Info":
					is_pano = 1
				
				entry_data = data[8+entry_offset:]
				
				if args.dump:
					print("Dumping: %s" % entry_name)
					with open(file_name + '_' + entry_name, 'wb') as f:
						f.write(entry_data)

			if (not is_pano) and (version < 106): #S8+ stopped adding this entry with trailer v106
				print(file_basename + ': Not a Samsung panorama')
				continue
			
			dataPos = dirPos - firstBlock
			dirLen = endPos - dataPos
			
			eoi = struct.unpack_from(">H",b[dataPos-2:dataPos])[0]
			if eoi == 0xffd9:
				print(file_basename + ': Already has EOI, not a defective Samsung panorama')
				continue
			else:
				print(file_basename + ': Inserting EOI to correct defective Samsung panorama')
				if not args.force:
					shutil.copy(file_fullname, file_name + '_orig.jpg')

				if args.overwrite:
					fh.write(b[0:dataPos])
					fh.write(bytearray(b'\xff\xd9'))
					fh.write(b[dataPos:])
				else:
					with open(file_name + '_fix_eoi.jpg', 'wb') as f:
							f.write(b[0:dataPos])
							f.write(bytearray(b'\xff\xd9'))
							f.write(b[dataPos:])
				m.close()
				fh.close()

parser = argparse.ArgumentParser(description='fixes Samsung\'s broken Panorama jpgs by adding EOI markers at the end of the file')
parser.add_argument('path', help='file or folderpath')
parser.add_argument('-d', '--dump', help='dumps Samsung specific data that is added to the image',action="store_true")
parser.add_argument('-R','-r','--recursive',action="store_true")
parser.add_argument('-o','--overwrite',help='overwrite orginial file',action="store_true")
parser.add_argument('-f','--force',help='do not create a backup of the original panorama',action="store_true")
args = parser.parse_args()

if os.path.isdir(args.path):
	filelist=[]
	if args.recursive:       
		for root, dirs, files in os.walk(args.path):
			for file in files:
				if file.endswith(".jpg"):
					filelist.append(os.path.join(root, file)) 
	else:
		for file in os.listdir(args.path):
			if file.endswith(".jpg"):
				filelist.append(os.path.join(args.path, file))
	if len(filelist) > 0:
		print ("Checking " , len(filelist), " jpg(s)")
		addEOF(filelist)
	else:
		print('Couldn\'t find any files with Samsung\'s panoramas standard .jpg extension')	

elif os.path.isfile(args.path):  
	if args.path.endswith(".jpg"):
		addEOF([args.path])
	else:
		print(file_basename + ': Doesn\'t have Samsung\'s panoramas standard .jpg extension')
		exit()
else:  
	print("This is not a valid file or folder path")
	exit()