Convert card1 3DS to card2

card1to2.py

import os,sys,struct,subprocess
print("\ncard1to2\nby Glitch\nTrimming feature by Jdbye\n")

filename=sys.argv[1]
f=open(filename,"rb+")
MB=0x100000

def num2string(n,size):
	ret=""
	for i in range(size):
		ret+=chr(n & 0xFF)
		n>>=8
	return ret

def string2list(n):
	ret=[0x0]*len(n)
	count=0
	for i in n:
		ret[count]=ord(n[count])
		count+=1
	return ret
	
def endianSwitch(n):
	return n[::-1]

def hex2value(n):
	return int(n.encode("hex"),16)

def grabData(off,size):
	f.seek(off)
	offset=f.read(size)
	return offset

if hex2value(grabData(0x18D,1)) == 2:
	choice=input("This game is already Card 2 type, but can be trimmed.\n\nW If you would like to adjust the save offset and trim the rom, type 1 then enter if you're ready (THIS WILL DELETE ANY EXISTING SAVE): ")
else:
	choice=input("Card 1 type game detected.\n\nWould you like to convert it to a card 2 game that saves inside its the ROM?\nMake sure you backup any existing data before proceeding in case something goes wrong with the conversion. Enter 1 to convert: ")

if choice != 1:
	print("Exiting...")
	sys.exit()

if hex2value(grabData(0x18B,1)):
	f.seek(0x18B)
	f.write(chr(2))
	
f.seek(0x18D)
f.write(chr(2))

if hex2value(grabData(0x18F,1)):
	f.seek(0x18F)
	f.write(chr(2))

dataSize=0
dataSize=hex2value(endianSwitch(grabData(0x300,4)))
saveOffset=(dataSize / MB)*MB+MB
padOffset=saveOffset + (MB*16)
mediaUnitOffset=saveOffset / 0x200

f.seek(0x200)
f.write(num2string(mediaUnitOffset,4))

#print hex(dataSize),hex(saveOffset),hex(mediaUnitOffset)

print("\nDATASIZE: "+str(hex(dataSize)))
print("NEW CARD2 SAVE OFFSET: "+str(hex(saveOffset)))
print("NEW FILE SIZE: "+str(hex(padOffset)))
print
f.close()
print("Calling Trunc "+filename+" "+str(padOffset))
print(subprocess.check_output(['Trunc.exe', filename, str(padOffset)],stderr=subprocess.STDOUT,shell=True))
raw_input("Done.")