The CRC can be re-calculated if you want to update the modules with new information.
Meaning that if you want to change a module, like the module containing the serial number or password or whatever, and you edit that data, you will then have to re-calculate the checksum of it to send it back to the drive ...
You should implement that too on your tool, because if you want to change modules and if you edit them with hex-editor then the CRC will not match, unless you re-calculate it, right ?

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^^ at this moment I don't know if the CRC update isn't handled by the firmware if you we use the standard module update VSC function. the second way it's to write the SA directly by pcs_write function at the start point of the module on the platter.

what I mean is that if I have a mod file on my hdd...and change something to it, I can then, write it to the SA in 2 ways: 1.a special vsc command...or 2. a simple data write using also a vsc command. as you can see at a previous post of mine, changing PUIS byte in flash, is handled by the firmware which does the modifications and fix the crc of the flash module. they have a special command for changing some flags, but I could have done it by downloading the mod..changing it by myself and uploading it again.

by the way, do you now if wd roms larger than 192kb exist?

Look at the menu of WDR 5.3 ....
Maybe they anticipated the need to read bigger ROM in the future .... Or else they already exist

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I believe that there's now way to know what's the bios size. that vsc command simply reads the flash image mapped on dram memory. I could do some tests, starting downloading first 128..then 192...then 256, and perform a checkrom() for the downloaded rom file to see if it's complete, but this will take some time. It's a little bit confusing for a user to select what's the rom size. that's why I search a way to simply avoid that drop/list. it would be nice.

You are doing great
Hope to be able to test your WD app sometime soon
Keep up with the good work.

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louis, the rom size is (mod109 size -1) *512 bytes.

qintl, on a lower perspective, perhaps. but what we do with the non-royl firmware, the 128k ones? there isn't any mod 109. we treat this situation as 128k? I mean..what returns false when asking mod109...it's a 128k rom? What if we can't access the SA? you know that he rom can be dumped even without access to SA

btw, I found a rom which seems to be old enough not to have any trace of mod's at the end of it. more, it doesn't fit to my description form here. the sizes seems to be on 3 bytes instead 4.

FWIW, ROYL ROMs appear to store the starting address of the block of ROM MODs near the beginning of the ROM.

In the following example, the double word at offset 0x410 contains 0x0002F89B which is where MOD OD is located.

download/file.php?id=4482

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news. the donor it's gone too. played around today with it when implementing SA modules writing. watched a football match then when started again the work, I found it not responding to commands. after reboot it makes exactly like the old one.

Cool !

And i bet that you don't have a way to put the drive in "safe mode" and send the permanet overlay to RAM ....

If the problem is just overwritten modules or damage firmware due to your program testing i might be able to ressurect your test drive (for free) if you want to ship it to my country. Of course that it will not solve the head problem....

What do you mean by "makes exactly like the old one" ? I don't think that you have killed the heads just by playing with the firmware, i'm assuming you damaged the road map or the head map or something like that on the process of writting to firmware, so should be easy to fix with "decent" tools. You will need the ability to load overlays to RAM and execute them from a file, assuming the ones on SA are gone due to your "testing" .....
I don't mind to take a look ....

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5 rounds of 2 clicks. then becomes redy in kernel mode...and I can play with the WDC ROM as with the old one.

not reading with any heads..and throwing THE ERROR : VSC error code not decoded for : 0x4341...while reading track -1

I have all the ways...but first I must understand what's the safe mode...and what's the "permanent overlay" and how to put it on RAM. I'll' code those functions if needed.

I have tested the writing only on one module 0xFC, chosen carefully...it was empty...only the header..and nothing inside. I found that the vsc write module fixes automatically the header..it computes the crc, and if the header it's too bogus..it won't accept the file

The head map it's in the Mod 0xA which it's in the ROM firmware. the rom firmware has all it's needed to access the SA. the adaptives to the ZONE 0 (SA) are inside mod 0x47 at the end of the rom.

So, what is your guess ? I doubt that you have killed the 4 heads with testing.
My guess is that you have write something on the wrong location and the original module needed for the drive to work is now gone ...

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Can you read the modules with 3.0 ?

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well..I did some coding...and some changes to the sourcecode (some proved to be wrong)...but I forgot that I was debugging exactly the write mod function...so it's possible that something went wrong on SA.

I ll test 3.0

3.0 will most likely fail if drive is clicking and can't access the SA. You will need better tools to load overlay from exterior file and only then you will be able to re-gain access to SA and correct the mess that you have done there.

I trully doubt that the rest of the head or even head 0 have died due to your experiments. It must be something SA related, like you have written to the wrong module or you wrote as a track and it clear the modules on that track, etc ....
I can't guess without looking at it.
You will need better tools.

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00FC = Dr

Importance D modules are the ones not needed to the normal operation of the drive. If you damaged that module it shouldn't make any diference in the working of the drive.

00FC=Factory selfscan module

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Did you check on the Road Map where the molule is located on the platter ? Because i don't think the firmware will just put the module on the correct place if you just say "Write FC" module.
My guess is that you have written your "FC" module on the place that was ocupied by a critical module and that one now is gone ....
Does it make sense ?

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I think that you can use that TREX that you have to load the perm. overlay. Or buy a full Sediv, or salvation, or DFL ....

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I've fixed it. I did a rom file compare. it was the mod 47 (sa adaptives) at the end of the rom...screwed up! I copied the mod 47 from a good dump, and updated using my app ..but didn't worked first time (after a reboot...perhaps requires a power down?). I swapped the old PCB and it started with that one without clicking (kernel mode) but I could access the SA. When I've put again its own PCB that I previously fixed..it started with this too..and it show fine the model number



NO...I'll explain. The firmware with its "write mod" vsc..lets you put the mod exactly in the same place. more..it doesn't allow to change its size. that's why it's safe. at a later time I'll have to code a function which allows adding any size mods..at any empty location...but this will involve many things..like finding a good..safe place in SA...then..adding an entry in mod01...the writing the file with chs..at specified cylinder head sector size etc.

that "write mod vsc"...also changes the mods (a,30,47 d) inside the rom firmware

Cool !
Rebbot normally will not work, you have to power down/up for it to load the ROM again. a system reboot will not stop the drive from spinning or lose the RAM state.

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