Skipped password

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zburget
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Location: Czech Republic

Re: Skipped password

Postby zburget » Tue Jul 18, 2023 2:29 pm

SFP module is single page (in A2 block). A0 block is always singlepage in SFP, or not?
Zbyněk Burget

ArT
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Re: Skipped password

Postby ArT » Wed Jul 19, 2023 9:34 am

In A2 block at addr 0x7F is page select byte (for paged SFPs). Sometimes page is "mirrored", it means that A0 block upper/lower is mirror of page in A2 block and to change A2 block you need to change X page directly. But honestly, I do not know why it's not working in this SFP when password is provided. The strange thing is that it overwrites manufacturer name once during brute forcing. Maybe it requires specific time delays during write - you can make some tests directly with custom script tool (first operation should be write password and second operation some test write with adjusted delays). I can make some own tests if you could send me this SFP for tests.

zburget
Posts: 27
Joined: Thu Mar 09, 2023 10:19 am
Location: Czech Republic

Re: Skipped password

Postby zburget » Fri Jul 21, 2023 12:49 pm

O.k.
I tried custom scripts and I think I figured out how this SFP module behaves.
After entering the password only one write command is accepted (immediately after entering the password).
The standard write process writes the block in 4 byte chunks. Only the first of these chunks is written.
When I try to write 8 bytes in one operation, the writing goes fine.
How I write data from buffer? If I check option "Import write bytes from buffer", into script is added row DATA:BUFFER; but nothing is written.
When I try to write password and in the next operation 256 bytes from buffer, I get error "Buffer size is to small or provide offset 4 is out of range."

Code: Select all

#SCRIPT HEADER;
SCRIPT:v1.8.1;
#HARDWARE SETTINGS;
HW:I2C,3.2V,SLOW;

//Password operation for SFP/QSFP/XFP/OSFP (block #A2h, addr #7Ah)
#OPERATION;
SW:1,3,0,0,80,0,40,0,0,500;
INSTR:A2,7A;
DATA:11,22,33,44;
#OPERATION;
SW:1,255,0,0,80,0,40,0,0,500;
INSTR:A0,00;
DATA:BUFFER;



Here, my assumption was confirmed that if option "Enter current password" is checked, the password is automatically written at begin of write process, but always to the address A2/7B, not to the address specified in the corresponding field. It's also visible in the script window, which I didn't notice before, I didn't realize it was there. IMHO this is the bug.

…how I can generate script header after deleting it? There's no way to get header from parameters in "Hardware settings" part of window.
Zbyněk Burget


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