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Best Hex Editor for ROMs?

Started by merlinkv, 11:24, 02 March 16

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merlinkv

Hi,

What's the best Hex editor (Windows) for ROMs ... I want to do some jobs on my ROM images to test it on X-MEM ....  :)

robcfg


Bryce

Lots of doubt. There are many to choose from. I use the editor in Prog-Express from Batronix: Software - Prog-Express

It's made for Batronix programmers, but it's freeware and the editor etc works without needing a programmer. It can also calculate and insert Checksums and even unique serial numbers.

Bryce.

Kris

Use to edit several files type with HxD as well.......

merlinkv

OK guys.

Thanks for the info... I will try later at home.

To start I want to do some changes in ParaDOS 1.2 following the instructions from here: ParaDOS 1.2

QuoteBit 4 - (0) Bit 2 Selects ROMDOS D1/IBM, (1) Bit 2 Selects Vortex/PCW
Bit 3 - (0) Disable, (1)Enable Ultraform format rather than ROMDOS D10 (*Config says D1)
Bit 2 - (0) Disable, (1)Enable IBM format rather than ROMDOS D1 (*Config says D10).
Bit 1 - (0) Disable, (1)Enable extended DATA and SYSTEM formats (Electro Formats)
Bit 0 - Drive configuration (DDB) usage affected by formats. (0 = Unlocked, 1 = Locked)

Vortex, PCW (SS40) and PCW (DS80) are new to ParaDOS 1.2.

So to make a temporary change to the drive definition, poke &baff or &bafe with the new value. To
make a semi-permanent change, poke &bafd or &bafc and the corresponding byte at &baff or
&bafe. To make a permanent change, change the ROM at address #3ffe (DDB) or #3ffd (DPB). If these
values are changed, the ROM checksum at #3fff should be adjusted accordingly.

The correct default values for 40 track, single-sided drive B should be 0 and 0.

To allow 80 track, double-sided discs to be used in Drive B: use DDB=#03. Disabling Electro
formats allows 40 track, single-sided DATA and SYSTEM format discs to be used in drive B

Specially I have doubts to calculate the checksum at #3FFF.


Thanks again  :)

merlinkv

I will try also with this one XVI32 2.55 ...  :)

TotO

You can edit a CPC ROM, using the EDITOR tool from the X-MEM floppy disc.
"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

Executioner

Quote from: merlinkv on 12:07, 02 March 16
Specially I have doubts to calculate the checksum at #3FFF.

Subtract the current bytes at #3FFD (DPB) and #3FFE (DDB) from the checksum byte at #3FFF, modify them, then add it back in. It's just a simple checksum of all bytes (#3FFF) = SUM(0..#3FFE).

merlinkv

#8
I have made next changes in ParaDOS 1.2 rom:

#3FFD = &02 / 00000010
#3FFE = &03 / 00000011

Te correct checksum (8 bit) for the whole file will be:  #3FFF = &OC / 00001100 ?? or &97 / 10010111

Other example:

#3FFD = &12 / 00010010
#3FFE = &03 / 00000011

Te correct checksum (8 bit) for the whole file will be:  #3FFF = &A3 / 10100011 ??
or &97 / 10010111 (8 bit checksum of all blocks minus #3FFF)

Sorry, I know is like a noob question, but too may years without working on Hex & Binary files .....
:picard:

merlinkv

#9
Quote from: Executioner on 12:59, 02 March 16
Subtract the current bytes at #3FFD (DPB) and #3FFE (DDB) from the checksum byte at #3FFF, modify them, then add it back in. It's just a simple checksum of all bytes (#3FFF) = SUM(0..#3FFE).


Wll I've made a test rom following your post ....


- Original value at #3FFF = &E5


- &E5-&12-&03 = &D0 (I'm not sure 100%)


Anyway, ROM burned with #3FFF = &D0 then flashed in X-MEM ....it appears like working fine : Read, write, copy .....


Edited: &D0 fails ... then reflashed wwoth #3FFF = &A3 ... working fine now  :)  crossing fingers

merlinkv

#10
Well, finally I have found my setup thanks to @all for the Hex Editors recommendations ...

- Original values: #3FFF = &E5, #3FFD = &00, #3FFE = &03

- My new value at #3FFD = &02 (ELECTRO Formats, ROMDOS D1 & ROMDOS D10 = Enabled)

- New checksum at #3FFF = &E7

My new ParaDOS 1.2 is working 100%






Executioner

Is the original values are #00, #03 and the checksum is #E5, then subtracting the original values gives #E5 - #00 - #03 = #E2.

With the new values of #02, #03, adding them back in you get #E2 + #02 + #03 = #E7, so you are correct.

For the past 20 years ParaDOS had the wrong checksum anyway, so I wouldn't be too concerned even if you do get it wrong, it will just annoy TFM's ROM Manager.

merlinkv

#12
Thanks again for your help mate  :)

Now I will try with new options .... but I will use WinApe to test it (is not a real CPC, but not bad for testing purpouses).  :D

merlinkv

#13
Hello,
I'm doing some jobs with ROM's but after log time I've forget how to do some task ...  :picard: :picard: :picard:

Mi idea is to patch the ParaDOS 1.2 to:

- Drive A -> Standard 3" disk, 40 tracks, one side (nothing to change)
- Drive B -> 3.5" drive with Vortex 720Kb format

What I need to do to change the default format to drive B to Vortex and set it as permanent?

Thanks & Kind Regards.

merlinkv

Hello,
Job done! Everything is OK.

TotO

#15
The X-MEM EDITOR program provided into its DSK allows to do that task from the CPC.
"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

Ast

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All friends are welcome !

merlinkv

#17
Hello,

Thanks.

I have done the job with HxD because I need to make changes on ParaDOSFile.rom to make a custom rom to be recorded on one W27C512 (I have a mod inside the CPC that allow to change internally 4xLower_ROM0 & 4xROM7 on a single & small PCB).

Now, I have two versions (with correct checksums), one for RomDOS and other for Vortex defaults.

Thanks again  :)

GUNHED

#18
Quote from: merlinkv on 12:07, 02 March 16
Specially I have doubts to calculate the checksum at #3FFF.
You can use the ROManager to implement checksums at the last byte of a ROM.

But why using apps for the PC? There are much good tools for the CPC.  :)


Quote from: merlinkv on 15:46, 10 February 20
Now, I have two versions (with correct checksums), one for RomDOS and other for Vortex defaults.


You can look for VaraDOS (that's the ParaDOS with Vortex formats enables). Aside of X-DDOS it's my favorite.  :)
http://futureos.de --> Get the revolutionary FutureOS (Update: 2023.11.30)
http://futureos.cpc-live.com/files/LambdaSpeak_RSX_by_TFM.zip --> Get the RSX-ROM for LambdaSpeak :-) (Updated: 2021.12.26)

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