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 Post subject: Re: Data Recovery Digitech Jamman Stereo (guitar pedal)
PostPosted: August 9th, 2019, 20:00 
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Could we see an example of a header and footer from phrase.wav ?

BTW, here is your broken URL:

http://www.at91.com/viewtopic.php?f=9&t=29088

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 Post subject: Re: Data Recovery Digitech Jamman Stereo (guitar pedal)
PostPosted: August 9th, 2019, 22:55 
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framp wrote:
Just an update for everybody facing a similar issue: I managed to login into the looper via UART. The looper is runnign QNX, a posix compliant Unix. I was able to dump the NAND data and a tool called etfsctl.

How did you dump the NAND?

Did you dd the NAND "drive" to an SD card?

Did you copy (cat) individual files to your SD card?

You say you scanned your dump for RIFF headers. Do the unplayable WAVs correspond to deleted loop data that were discovered by the scan?

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 Post subject: Re: Data Recovery Digitech Jamman Stereo (guitar pedal)
PostPosted: August 9th, 2019, 23:22 
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duplicate post


Last edited by HaQue on August 9th, 2019, 23:25, edited 1 time in total.

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 Post subject: Re: Data Recovery Digitech Jamman Stereo (guitar pedal)
PostPosted: August 9th, 2019, 23:24 
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I haven't been following the thread, but saw recent posts about first dumping a NAND, then issues playing files.

I think Franc may be alluding to this, but there is a few possible reasons:

1) the format could be different than straight .wav
2) post processing done by decoder to not use all of the .wav spec or in a different manner than intended
3) your dump included information such as SA bytes or ECC or something that further needs to be stripped out
4) files are not stored in a totally concurrent fashion... I have seen recently while hacking some games consoles that ROM files for example have a block of DATA and if the ROM is bigger than this, the next block is stored somewhere else, not straight after.
5) your dump might be ok, but not ECC corrected, so bit errors are present. (Linux systems that use NAND should have this built in though at a driver level)
6) may be some binary to ascii conversion happening, but I would think files would be totally screwed up if this were the case (thinking like specifying BINARY option in some rudimentary older protocals)

kudos or getting this far. I remember when I first got a prompt from a Microvax 3400 after a friend came across 2 complete but disassembled systems. right at the start of accessable internet, searching was in infancy, and I had help from a Tafe college lecturer that correctly identified the plug that looked like a LAN port as a terminal adapter port. not knowing anything about unix, terminals etc. this opened up a whole new world


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 Post subject: Re: Data Recovery Digitech Jamman Stereo (guitar pedal)
PostPosted: October 5th, 2019, 7:06 
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Just a final update: I finally managed to extract the NAND data from the looper and also spent a lot of time to understand the dump format (QNX etfs filesystem) and to extract the files from the raw dump. Unfortunately the transactions in the dump which contained the data of the deleted loops was cleared with 0xff :evil: I frankly have no idea why this happened. Looks like the data was cleared in parallel when the transaction metadata was cleared.

As I said I spent a lot of time understanding the etfs format and design. The code I created to recover all files which had transactions in the raw etfs dump is available here in github. It's not very elegant code because I had a lot of trial and error coding loops but finally it recovers the files. Maybe it's useful for somebody in the future who has to recover data from an etfs filesystem.


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 Post subject: Re: Data Recovery Digitech Jamman Stereo (guitar pedal)
PostPosted: October 6th, 2019, 17:39 
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framp wrote:
As I said I spent a lot of time understanding the etfs format and design. The code I created to recover all files which had transactions in the raw etfs dump is available here in github. It's not very elegant code because I had a lot of trial and error coding loops but finally it recovers the files. Maybe it's useful for somebody in the future who has to recover data from an etfs filesystem.

Many thanks!

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 Post subject: Re: Data Recovery Digitech Jamman Stereo (guitar pedal)
PostPosted: October 10th, 2019, 13:57 
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I just detected your update. I unfortunately missed to enable thread update notification with eMail :?
fzabkar wrote:
How did you dump the NAND?

Code:
etfsctl -d /dev/etfs2 -R /mnt/sdfs/etfs2.img

See http://www.qnx.com/developers/docs/6.5. ... fsctl.html
Quote:
Did you dd the NAND "drive" to an SD card?

Hm ... no, I used the oficial QNX command. Do you think it's worth to give it a try to get more data?
Quote:
Did you copy (cat) individual files to your SD card?

Yes, but that way I only got the existing files, not the deleted files.
Quote:
You say you scanned your dump for RIFF headers. Do the unplayable WAVs correspond to deleted loop data that were discovered by the scan?

This scan was useless because the way etfs works. Whenever you update a data block with a RIFF header for a WAV file a new data block is written with the updated data including the RIFF header and the old data block is unlinked from the file. So every update of a wav header data block creates a new scan match as long as the deleted data block is not cleared or reused by another file.


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 Post subject: Re: Data Recovery Digitech Jamman Stereo (guitar pedal)
PostPosted: October 10th, 2019, 14:07 
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Same for you - missed you comment - sorry.
HaQue wrote:
1) the format could be different than straight .wav
2) post processing done by decoder to not use all of the .wav spec or in a different manner than intended

I was able to reciver the not deleted fie from the NAND dump. There was some special handling required to extract the file but the format was correct.
Quote:
3) your dump included information such as SA bytes or ECC or something that further needs to be stripped out

That's done by etfsctl to get a device independent representation of the etfs content.
Quote:
4) files are not stored in a totally concurrent fashion... I have seen recently while hacking some games consoles that ROM files for example have a block of DATA and if the ROM is bigger than this, the next block is stored somewhere else, not straight after.

I assume all the data is stored in the NAND.
Quote:
5) your dump might be ok, but not ECC corrected, so bit errors are present. (Linux systems that use NAND should have this built in though at a driver level)

Extraction of non deleted files was possible and I detected no ECC errors
Quote:
6) may be some binary to ascii conversion happening, but I would think files would be totally screwed up if this were the case (thinking like specifying BINARY option in some rudimentary older protocals)

I had to use little endian format and everything was OK.

Quote:
kudos or getting this far. I remember when I first got a prompt from a Microvax 3400 after a friend came across 2 complete but disassembled systems. right at the start of accessable internet, searching was in infancy, and I had help from a Tafe college lecturer that correctly identified the plug that looked like a LAN port as a terminal adapter port. not knowing anything about unix, terminals etc. this opened up a whole new world

Yes, I was glad when I managed to enter the Unix system via console and to find some doc and C code in the net about etfs and etfsctl.


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 Post subject: Re: Data Recovery Digitech Jamman Stereo (guitar pedal)
PostPosted: October 11th, 2019, 3:35 
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@fzabkar I tried dd and got an empty output file. Actually I remembered I already tried this when I got access to the system. That's the tool to clone a hard disk for data recovery actions. But looks like the etfs doesn't comply with the Linux device protocol and returns end of device immediately. I tried to find the source code for etfsctl to get an idea how the data can be extracted from NAND but failed :(

Comment for mods/admins: How many comments do I have to write until my posts will not require an approval from you any more? It's really annoying :?


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 Post subject: Re: Data Recovery Digitech Jamman Stereo (guitar pedal)
PostPosted: June 3rd, 2020, 20:53 
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Hi, did you tried to see connect it to jammanager?


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 Post subject: Re: Data Recovery Digitech Jamman Stereo (guitar pedal)
PostPosted: June 5th, 2020, 13:22 
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Yes, but that didn't help because I wasn't able to see the deleted files.

Finally I wrote a program to retrieve the existing data from NAND and detected there was not any byte any more from the old files.


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 Post subject: Re: Data Recovery Digitech Jamman Stereo (guitar pedal)
PostPosted: June 15th, 2020, 3:21 
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Well, this wasn't my Jamman Stereo. I would have created a backup on a memory card on a regular base. But my son who asked me for help didn't do this - unfortunately :( So the only source for data recovery was the NAND which unfortunately was cleaned up at some point in time :evil:


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 Post subject: Re: Data Recovery Digitech Jamman Stereo (guitar pedal)
PostPosted: May 29th, 2022, 16:44 
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framp wrote:
Well, this wasn't my Jamman Stereo. I would have created a backup on a memory card on a regular base. But my son who asked me for help didn't do this - unfortunately :( So the only source for data recovery was the NAND which unfortunately was cleaned up at some point in time :evil:

Were you able to get the Sound files out of the unit after all?


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 Post subject: Re: Data Recovery Digitech Jamman Stereo (guitar pedal)
PostPosted: June 4th, 2022, 15:07 
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Unfortunately no. I was able to recover old files and the sample files :cry:


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 Post subject: Re: Data Recovery Digitech Jamman Stereo (guitar pedal)
PostPosted: March 24th, 2024, 20:44 
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Hi,folks lets breathe life into old thread I need your expertise pls. Ive got jamman stereo looper that I used a a handful of years with no issues whatsoever . Well , it was such a day just plug it in and to my psu ... error on screen . I began searching for info then found this data recovery topic . But there is a big difference between cases . But fist things first . My internal memory is fully accessible via jamman xt so I copied everything to my pc and sc card as well . There's time for experiment now . What was done before anything else is attempt to default settings of course it didn't work out . All right then I tried to update firmware over jamman xt since it has old 1.3 version , in the moment of clicking on firmware update check now causing the program to crash immediately ( tested on both WIN 7 X65 and WIN 10 with same result ) . I took it apart and pulled the pcb board out and checked every component for soldering cracks blobs etc , nothing suspicious . I then moved on to voltage measures , everything within a tolerance (used datasheets provided in this topic as reference) . Well , what we have in the dry residue , control panel seems responds and works , switches up/down increase and decrease lcd loop counter. Also looper recognized when hook up over usb and I can erase any loop from internal memory but no recording anymore , and sd card works read/write when engaged green led on . A diagram posted here shows than Micron nand and sdram are sitting on the same bus . Could be a nand boot code is corrupt ? I can swap this bga chip with brand new no problem but will atmel mpu boot up with blank nand and download firmware via usb ? as to sdram nanya , can we make assumption that both chips are alive as I said I can copy any recorded loop from internal memory and back . Needles to say that Digitech didn't even replay to me , what I wanted is to try very last resort flashing boot firmwire from sd card that I couldn't download from resources . have any ideas how to fix it pls share your thoughts here . I will be very grateful


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