Seagate : How to backup firmware

[samsam]

Hello,
i'm newbie (sorry)
I receive my usb to ttl adapter
I plug, with various HDD and all is ok
Now I want to backup my original firmware before try to play with it.

I attemp with sediv (free version) but when i want to read I have the message 'only full version'

If I have understand, the firmware is composed by 3 part:
1 in rom, and 2 in hdd track (no direct access track "-41").

when i attemp to do lot of command , I have :

"INVALID Cert Disk Code - ROM resident revision required APN140"

if i understand, i need to put an cert in rom (or on track ?) before send order to read firmware ?

thanks for your help

ps: Test Disk information
Barracuda 7200.ES
GALAXY3D
firm :3.APPZ
serial: 9QG84TZN

on boot disk say me :
Reset
4096k x 32 DRAM
GALAXY - 1_Disk S-6D 02-02-07_11:01

on ^L :
2>GALAXY3D - 3_Disk 3.APPZ 12-03-07_17:44 APN,GX_3D_6H_S,14
Built for GALAXY3D,PITKIN,Redback,TI1843 PreAmp,Agere7539 PreAmp,McKinleyDT,3Disk,220 Servos,7200RPM,8Pole,133MHz,RwFeat=0002,VBAR

[samsam]

this hdd work fine
i don't think there is a damaged cert track but it's possible it was an IBM remanufactured seagate.

For the paid version software, I read that lot of soft allow to read the firmware but we need to pay to write it, correct ?

stcom is ok, but my version is not translated , (i use screeshot to know witch button to press).

I think all my hdd is older than F3 arch.

In my mind,i want to bkp all firm that I found and upload to this site, but if my bkp is corrupt, how can I detect it since I can't write it back to hdd ?

[samsam]

ok for the cert , I d'ont know it's possite sata work with cert damaged , thanks for sharing this information !

for the cert: it's writting on track ? where can I find the address to attempt to read ?

"loading firmware to RAM from F> and select the box to write to disk."
can you explain me more please ?

on stcom I use the "backup fw" and I check all the checkbox how can I verifiy my backup file are correct ?
there is a crc check tolls somewhere ?

thanks

[samsam]

I know your site , i'm member to
I go to search .
About basic understanding barracuda working, do you have doc/datasheet/info somewhere ?

thanks

[samsam]

PC3K UDMA english manuals have barracuda schematic block
but it's... in russian lol
thanks for the keyword, i go to google

[samsam]

If you want I will be happy to write this tutorial with you