Author Topic: Help required to fix Checksum on a Utility rom Please  (Read 801 times)

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Offline Audronic

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Hi All
Help required to fix Checksum on a Utility rom Please.
Dropbox - UTILITY.ROM.zip


SORTED, The ROM is Faulty.


Thanks     Ray
« Last Edit: 07:36, 08 January 16 by Audronic »
Procrastinators Unite,
If it Ain't Broke PLEASE Don't Fix it.
I keep telling you I am Not Pedantic.
As I Live " Down Under " I Take my Gravity Tablets and Wear my Magnetic Boots to Keep me from Falling off.

Offline TFM

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Re: Help required to fix Checksum on a Utility rom Please
« Reply #1 on: 21:16, 08 January 16 »
You basically add the values from &C000 to &FFFE and keep the result in 8 bit. This byte then gets written to &FFFF.


Or you can use ROManager 2.14 to adjust the check-sum using the Test-ROM option.
TFM of FutureSoft
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Offline Audronic

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Re: Help required to fix Checksum on a Utility rom Please
« Reply #2 on: 01:00, 09 January 16 »
@TFM


Thanks for the info, I did it the hard way
I used MegaFlash Romanager 464/664 Ver 1.45 (TFM)


To Test the rom, Update checksum, Dump rom to disk.
Compared   Rom1 Faulty CheckSum with Rom1 fixed CheckSum
Found the Byte that had been modified at &FFFF.


Thanks    Ray
Procrastinators Unite,
If it Ain't Broke PLEASE Don't Fix it.
I keep telling you I am Not Pedantic.
As I Live " Down Under " I Take my Gravity Tablets and Wear my Magnetic Boots to Keep me from Falling off.