All times are UTC - 5 hours [ DST ]




Post new topic Reply to topic  [ 3 posts ] 
Author Message
 Post subject: Allwinner A13
PostPosted: November 5th, 2018, 18:22 
Offline

Joined: November 5th, 2018, 13:44
Posts: 1
Location: Bretagne
Hello,
Does anybody has BCH parameters for Allwinner A13 nand flash controller ?
It's for Reread a STorex Ezee tablet nand flash (H27UCG8T2ATR-BC)
I have found the XOR key. But I can't found the ECC parameters
Thanks


Top
 Profile  
 
 Post subject: Re: Allwinner A13
PostPosted: November 7th, 2018, 1:37 
Offline

Joined: October 24th, 2009, 15:22
Posts: 583
Location: Poland
Yes, here it is. Should be in DB, I sent it some time ago to developers. They do not add it?


Attachments:
A13_1078(ecc50b)_4.zip [512 Bytes]
Downloaded 6 times

_________________
Odzyskiwanie danych
Top
 Profile  
 
 Post subject: Re: Allwinner A13
PostPosted: November 7th, 2018, 13:34 
Offline

Joined: January 23rd, 2018, 7:50
Posts: 2
Location: Poland
In unknown cases of ECC its worth to use codeword analysis tool. It's very easy and effective to use, Connect BCH element to physical image and as Payload you set assumed range of data area and eventually spare area if it exist, in Parity - range of ECC area (positions counted from 0). In this case it little more complicated because DA and Spare aren't in row. You can use offset to skip bytes between them (you have to shrink page size in codeword analyser settings as well). Polynomial is dec/hex representation of binary generation polynomial for parity bits e.g. 369d is binary 1 0111 0001 and polynomial for it is:

x^8 + x^6 + x^5+ x^4 + 1(x^0)

Degree is the value of highest power.

To choose correct degree for analyse add total length of payload and parity bytes for codeword ( in your case based on Michal's file it's 1028+50 = 1078 bytes and it's 8624 bits). 8624<16384 ( 2^14) so correct degree is 14.

You can also use predefined specific polynomial as well.
Result you receive will be in range 1-64 and it's ratio correctable codewords to tested codewrods (higher is better).


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 3 posts ] 

All times are UTC - 5 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group