Steveyzerman Posted August 31, 2005 Report Share Posted August 31, 2005 I need help editing the checksum or bypassing the checksum, please help. Quote Link to comment Share on other sites More sharing options...
wboy Posted September 1, 2005 Report Share Posted September 1, 2005 Refer to this post. Note, the checksum routine is bigger in 97 than 94 (used in the example), and the refering offset is at Hex 768 and not Hex 302. Ignoring the above, and if you want the you want the quick fix, find the last occurence of 4E71 and change it to 6602 (from memory).... I recommend you follow the stesp above though/ Quote Link to comment Share on other sites More sharing options...
Steveyzerman Posted September 1, 2005 Author Report Share Posted September 1, 2005 Refer to this post.Note, the checksum routine is bigger in 97 than 94 (used in the example), and the refering offset is at Hex 768 and not Hex 302. Ignoring the above, and if you want the you want the quick fix, find the last occurence of 4E71 and change it to 6602 (from memory).... I recommend you follow the stesp above though/ I tried that, but it did not work so well, Do you know the exact bin offset Quote Link to comment Share on other sites More sharing options...
wboy Posted September 2, 2005 Report Share Posted September 2, 2005 I tried that, but it did not work so well, Do you know the exact bin offset Hmmmm.... it should work if done properly. Oh well, here is another way.... Take a clean 97 rom (or atleast don't use the same rom you used to test the method above). Goto 1E253C Change the value 6602 to 4E71 I got it the wrong way around in my earlier post! Quote Link to comment Share on other sites More sharing options...
Steveyzerman Posted September 2, 2005 Author Report Share Posted September 2, 2005 Hey that worked, cheers! How did you know that anyway, how do you know about checksums of different games. Quote Link to comment Share on other sites More sharing options...
wboy Posted September 3, 2005 Report Share Posted September 3, 2005 Hey that worked, cheers!How did you know that anyway, how do you know about checksums of different games. I simply took some old game genie master codes for a few of the early NHL roms in the series. Working back what they did (they effiectively rom hack bytes dynamically when the game loads), all the master codes (needed to have other codes work) changed the checksum routine bytes 6602 to 4E71. This works for all EA games I've checked except for NHL & NFL 98, which have no checksum routines... and from that I learnt who to remove the checksum in all games (as per my linked topic instructions). Quote Link to comment Share on other sites More sharing options...
Steveyzerman Posted September 3, 2005 Author Report Share Posted September 3, 2005 does it work with the Fifa series Quote Link to comment Share on other sites More sharing options...
wboy Posted September 4, 2005 Report Share Posted September 4, 2005 does it work with the Fifa series Well I just checked the Genesis FIFA 95 and 98 and both have the common EA checksum routine as used in the NHL series. Simply do a find for 6602, goto the last occurence of it and change it to 4E71 (or remove it completely as in my more detailed instructions to make it load marginally quicker. ) I did a quick name edit test after doing so, and can confirm it will load. Quote Link to comment Share on other sites More sharing options...
Steveyzerman Posted September 7, 2005 Author Report Share Posted September 7, 2005 Thanks Quote Link to comment Share on other sites More sharing options...
deadmeow Posted November 13, 2006 Report Share Posted November 13, 2006 I have done the same thing too (game genie "master codes") also when hacking Madden roms. If you don't want to convert the Game Genie text to hex in your head, there is a Game Genie Code converter out there. Those codes come in handy. Quote Link to comment Share on other sites More sharing options...
shadowmeister Posted July 12, 2017 Report Share Posted July 12, 2017 Greetings! I just a read a post you made a while back regarding FIFA 95 and was hoping you could help me. I tried to follow your advice but I am a complete beginner in regards to Hex editing. Waaaaaaaaaaayyy back in 2005 you said: Quote Well I just checked the Genesis FIFA 95 and 98 and both have the common EA checksum routine as used in the NHL series. Simply do a find for 6602, goto the last occurence of it and change it to 4E71 (or remove it completely as in my more detailed instructions to make it load marginally quicker. ) I did a quick name edit test after doing so, and can confirm it will load. How would i do this? I have a trial version of Hex Editor Zero and was also trying to use the Free Online Hex Editor from - https://www.onlinehexeditor.com/ but when i search for 6602 I can no results. You have me pretty excited as I am trying to find a way to edit the players names/attributes etc and if you can get me closer to this goal I would be eternally grateful. regards. shadowmeister Quote Link to comment Share on other sites More sharing options...
shadowmeister Posted July 12, 2017 Report Share Posted July 12, 2017 thanks again wboy made my day Quote Link to comment Share on other sites More sharing options...
smozoma Posted July 12, 2017 Report Share Posted July 12, 2017 6 hours ago, shadowmeister said: Greetings! I just a read a post you made a while back regarding FIFA 95 and was hoping you could help me. I tried to follow your advice but I am a complete beginner in regards to Hex editing. Waaaaaaaaaaayyy back in 2005 you said: How would i do this? I have a trial version of Hex Editor Zero and was also trying to use the Free Online Hex Editor from - https://www.onlinehexeditor.com/ but when i search for 6602 I can no results. You have me pretty excited as I am trying to find a way to edit the players names/attributes etc and if you can get me closer to this goal I would be eternally grateful. regards. shadowmeister Three is a good free hex editor called "HxD" (for windows), if you don't want to use that trial software or online editor. (One small issue with hxd is you need to read the options carefully when doing a search as it tends to default to searching as text, not hex, and I think the "go to address" defaults to decimal not hex.. Which just aren't the defaults I would expect) Quote Link to comment Share on other sites More sharing options...
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