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Bolo
Joined: 05 Dec 2017 Posts: 727
Location: 506F6C616E64
Posted: Thu Jan 16, 2020 16:05 Post subject: Problem with ECC combine
Problem with ECC combine
Description of situation:
Let's say I read a chip. In first reading I have some red sectors (ECC can't correct), "ECC Fix" do not fix data in this secotrs, and this is OK.
In second reading with different voltage, read retry, etc., I have some single gray sectors (0xFF or 0x00), but also "ECC Fix" can correct some sectors that in the first read was unable to.
So we got two reading now. According to http://www.flash-extractor.com/manual/ecc/ software schould take good sectors from new dumps and write them to main dumps. But this not works as it schould when there are grey sectors (0xFF or 0x00). If there are gray sectors in second dump it will apply them onto dump and there are NO OPTION to fix it from this point - software will not change/fix GRAY->GREEN
And now, when I use ECC Combine, that gray sectors (0xFF) from second read are apply on Main dump (only if sector are red), and destroy this uncorectable data.
In the third reading with (different voltage, read retry, etc.), sectors that was red in first read, and gray in second read, now are green (correctable), but flash extractor can't apply this data to Main dumb, because earlier ECC Combine destroy this sectores, mark as (0xFF).
MAIN DUMP - INPUT DUMP
RED > GREEN - works OK
RED > GRAY (0xFF or 0x00) - not WORKS (demage dump so cannot be corrected even if they will be Green on next combine)
GRAY (0xFF or 0x00) > GREEN - not WORKS (demage dump so cannot be corrected even if they will be Green on next combine)
Questions:
1. Can you fix ECC Combine that if in input dump are grey sectors do not apply it on Main dump?
2. Can you add features for ECC Combine that if in Main dump are grey sectors (0xFF or 0x00) but in input dump after ECC fix this sectors are green, apply it on Main dump?
Photos descriptions:
foto 1. Main dump after ECC Combine where sectors are grey (0xFF of 0x00) - with sepecific voltage where in other part of dump data was correct
foto 2. Re Read where data are correct in this same part of dump, and are not apply on Main dump
Posted: Fri Jan 17, 2020 11:41 Post subject: Re: Problem with ECC combine
Bolo wrote:
1. Can you fix ECC Combine that if in input dump are grey sectors do not apply it on Main dump?
I treat it as memory malfunction situation
When voltage is lowered so much that memory start give wrong data
Thats why i disable ECC_Reread, that make read and combine automaticaly
I always say: read new dump. look ECC map. If you see there situation like on your uppper picture, do not use this dumps for combine
Bolo
Joined: 05 Dec 2017 Posts: 727
Location: 506F6C616E64
Posted: Fri Jan 17, 2020 17:05 Post subject:
But this input dump contains also over 30000 of fixed Green sectors with corrected data so will be good if in combine software will use ONLY Green sectors from Input dump and not gray
Bolo
Joined: 05 Dec 2017 Posts: 727
Location: 506F6C616E64
Posted: Tue Jan 21, 2020 0:36 Post subject:
Also what about feature from question 2....
2. Can you add features for ECC Combine that if in Main dump are grey sectors (0xFF or 0x00) but in input dump after ECC fix this sectors are green, it will works to apply it on Main dump?
Right now even if in Input those sectors are Green but in Main they are grey it will not apply green sectors on those parts.
Bolo
Joined: 05 Dec 2017 Posts: 727
Location: 506F6C616E64