File system structure - Info for investigation of Recovery - Bootable SD Card

Discussion in 'Sylvania Tablets' started by cfrockit, Mar 15, 2011.

  1. cfrockit

    cfrockit Member

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    Work in progress to find a Recovery image to install with a Bootable SD Card

    Update -
    See How to manually update SYNET7LP/SYTABEX7 to Android 2.2 "Froyo"

    If this seems simplistic it probably is because of my limited knowledge. I am learning as I go and any assistance is appreciated. There are other forums devoted to development but this site has the most participation related to this specific device. In reviewing many many sources I have made some discoveries regarding this tablet since it has a InfoTM CPU as does the Flytouch II, WOWpad, SuperPAD, Mid Tablet PC, ZT-180, and the disgo Tablet 6000.

    The tablet has several devices which hold different parts of the file system. These can be identified using these commands.

    Code:
    C:\adb shell
    # cat proc/mtd
    
    dev:    size   erasesize  name
     mtd0: 00200000 00080000 "ramdisk"
     mtd1: 00600000 00080000 "kernel"
     mtd2: 08000000 00080000 "resv"
     mtd3: 0c000000 00080000 "system"
     mtd4: 3d800000 00080000 "userdata"
     mtd5: 04000000 00080000 "cache"
     mtd6: 1ff00000 00080000 "Local-disk"
     mtd7: 00100000 00080000 "panic"
    In reviewing a firmware update for another InfoTM device I found this description of the file system.

    Code:
    #[alias]     [device]              [device2]           [partition_name]  [mount_point] [file_system]
     BOOT:       NULL                  NULL                boot              NULL          raw
     KERNEL:     /dev/block/mtdblock0  NULL                kernel            NULL          raw
     RAMDISK:    /dev/block/mtdblock1  NULL                ramdisk           NULL          raw
     RECOVERY:   /dev/block/mtdblock2  NULL                recovery          NULL          raw
     SYSTEM:     /dev/block/mtdblock3  NULL                system            /system       yaffs2
     DATA:       /dev/block/mtdblock4  NULL                userdata          /data         yaffs2
     CACHE:      /dev/block/mtdblock5  NULL                cache             /cache        yaffs2
     LOCAL:      /dev/block/mtdblock6  NULL                local             /local        yaffs2
     SDCARD:     /dev/block/mmcblk0p1  /dev/block/mmcblk0  NULL              /sdcard       vfat
     TMP:        NULL                  NULL                NULL              /tmp          tmpfs
     PACKAGE:    NULL                  NULL                NULL              NULL          package
    This now explains why attempts using unyaff to open the image file created by dumping mtd2 have failed.

    Using this HOWTO: Unpack, Edit, and Re-Pack Boot Images

    The extracted ramdisk image from the Sylvania reveals the following file structure which will look familiar to anyone who's examined their device layout (image below). So we know that device mtd0 is in fact ramdisk.


    $ramdisk7z.PNG

    In this post Firmware update 1480, instructions and download link, from a developers forum, they provide a link to a firmware of a similar device which includes instructions and utilities to create a bootable SD.

    Using the provided instructions and utilities from the downloaded file, I was able to create a SD card that boots!

    A 2 GB microSD was re-sized to 705 MB and the included "aben.start sector.001" file was incorporated into the "Clone Disk". It was then formatted FAT 32 with Format options - Quick Format checked. I copied only the uImage and userdata.img files to the card and inserted in tablet. Powering on the following was displayed.
    $D2uPG3.gif
    Booting from SD ...

    Burn file system finished

    Take off SD and reboot
    .

    Nothing was changed or burned in the process above. This was only a test for creating a bootable SD card that will work in this device once we have the correct image files. The test process DID NOT affect the original ability to do a complete factory reset.

    This as far as I have been able to take this effort. Any further insight to which of the images pulled from the Sylvania, if any, can be used in place of the images provided by in the example from the other device would allow creation of a working SD recovery for the Sylvania. A complete victory would be to find the magic combination which will all those missing an Recovery to successfully recover from SD.

    Where do we go from here to find/create the correct files for the Sylvania?
     
    Last edited: Apr 25, 2011
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  2. ImagineThat

    ImagineThat Junior Member

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    cfrockit - right on! I just installed ubuntu linux on a spare PC and have made it to the point of unpacking the mtd0 image, which is in fact the ramdisk. I'm curious if anyone heavy into development would be able to pick apart the init files to tell us anything useful about this Sylvania tab.

    I followed the instructions at HOWTO: Unpack, Edit, and Re-Pack Boot Images - Android Wiki also, but ended up figuring out that the mtd0 image was a uImage so you need to use a hex editor to strip off the u-boot header (the 64 bytes before 1F 8B). The remaining file can be extracted with
    Code:
    gunzip -c ../mtd0a.img | cpio -i
    That's slightly different than the earlier versions of Android boot images that had a 2k header, kernal, and then compressed ramdisk, which it appears the howto was written for.

    I found http://buffalo.nas-central.org/wiki/How_to_Extract_an_uImage useful, but I didn't use their script.
     
    Last edited: Mar 15, 2011
  3. ImagineThat

    ImagineThat Junior Member

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    I've dumped all 8 partition images and cannot unpack any of the ones that appear to be yaffs2 (like system or userdata). I tried unyaffs on all 8 for the heck of it, with no results.

    that's where I'm stuck.

    Nice work with the SD!
     
  4. st0ne

    st0ne Junior Member

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    Nice.... My question is this: Using just those 2 files... what DID it do to your system? Did it wipe out your apps and boot to the screen calibrate tool? I wonder if using just those 2 files will reset my internal memory?... hummm.... i might have to try...
    The files you used were extracted from a SYNET7LP right? Or was it a SYTABEX7? And where did you put them on the SD? in the android folder like the insts in the link say? Or in the root?
    Can you post those files? I would like to use files I know came from the ex7 or the LP7 rather than the ones floating around from others...
    Nice work! Thanks again!
     
    Last edited: Mar 16, 2011
  5. giveen

    giveen Junior Member

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    Great job, cfrockit!
     
  6. st0ne

    st0ne Junior Member

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    OK! After giving up and using a different SD card, the old I had was 2 gig and was used in an old phone and was throwing me errors.
    I now have a 4 gig SD and it cloned and formatted with out error. I followed the dirs you posted. with the "android" folder, and it worked the first time out of the gate!
    So when I put in the new SD and boot it goes through the burning images.
    When it's done it tells me to pop out the SD and reboot. I do, and first get a planet/space logo, then goes to a white screen. And Stays there.

    I am at the point were I need someone with a SYTABEX7 to ADB the files off of it and put together a folder like the "android" one!


    I am now going to try every combo of IMG file I have here and see what I can get.
     
  7. cfrockit

    cfrockit Member

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    This must be the Flytouch firmware boot splash image where our is the Sylvania animation so you've proved something burned. Is the any different reaction when applying the three finger factory reset?

    As you are aware the images for the SYNET7LP are here http://www.androidtablets.net/forum...g-clockwork-recovery-tablets-2.html#post31981 no one has offered up the EX7 dumps yet.


    One thought - the file names might need to match what was in the example folder.

    Good luck
     
  8. st0ne

    st0ne Junior Member

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    All of the links in that post lead to Dropbox 404 error file not found. So I don't have access to them. if you have them can you post them? Or anyone who got them before they got "lost"?

    I am seeing around the net different file names for things. I have seen uImage zImage ramdisk.img recovery.img recovery_rd.img (that one looks like it's the ramdisk renamed or it's the RD AND the recovery data) I don't know what files the SY tabs need to flash.
    The files that bricked my tab were Ramdisk.img/recovery.img/system.img/userdata.img and uImage with no file extension.
    From the prompts on the flash screen the things that were updated were the file system and the system. I didn't see any reference to userdata or recovery.
    I can not get either of my SYTABEX7's to connect to my PC with ADB. I can't seem to find the right drivers for WIN7 I think. I have tried all 3 of the ADB drivers: theAdb the bootloader and the composite drivers all fail to allow ADB to see my devices.
     
  9. ImagineThat

    ImagineThat Junior Member

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    I have all my images saved, I can work on posting them to some file sharing website, any ideas on a good FREE one?

    I understand your confusion. The images for the Sylvania are named as show up with you run "cat /proc/mtd", as cfrockit has shown in the first post here. Every device seems to name thinsg a little different. Here are some pointers to relate all these names to the Sylvania (anybody corret me if I'm wrong):

    mtd0 is named "ramdisk" and is the boot image/partition. It is a uImage file.

    mtd2 is most likely the recovery, but is named "resv" on this device for some reason. I haven't figured out what file type it is, I assumed yaffs2 but possibly it's some raw format??

    kernal, system, userdata are all what they say, and are similair names as other devices. Kernal is a uImage I believe; system and userdata appear to be yaffs2 but I cannot seem to unpack them.


    The only way that we've been able to get the SYNET7LP's to connect to ADB is through wifi, not through a direct USB connection. The instructions are floating around, I'll look for them and edit my post. Although, you need a working tablet with a wifi conenction for this to work, which is the big disadvantage of this over a direct USB connection.
     
  10. st0ne

    st0ne Junior Member

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    Yes the one EX7 is bricked right now from me flashing an android system that wasn't compatible. I have another one that I might have to set up with ADB WiFi... I ran into my 0.00b free mem on my bricked tab BEFORE I got to trying it WiFi.
    My goal here is to get all the stock system files off the working one and flashing it to the bricked one with the SD....
    Am I wishing on a star here?
     
  11. ImagineThat

    ImagineThat Junior Member

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    That sounds pretty logical to me. You can get all the partition images off your working tablet without using adb, if you wish:
    1) using a terminal emulator (there are some in the slideme market, or search online) type "cat /proc/mtd". This will list all the partitions. They may be different on yours.
    2) type "cat /dev/mtd/mtd# > /sdcard/NAME.img" replace # with the number of the partition, and NAME with whatever you want to call your file. This will place an image onto the root of your sd card. Note that you will need about 2 GB free on the card to copy all the partition images.

    Now you'll have each one backed up. As far as getting them onto your broken unit, you'll have to experiment with loading from the sd card as discussed above. If you're able to get to a command prompt or terminal emulator you can try the command "flash_image boot /sdcard/NAME.img" where boot is the name of the partition you're flashing (get from the cat /proc/mtd command) and NAME.img is your image file on the sd card.
     
  12. cfrockit

    cfrockit Member

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    The most recent update file that was downloaded but never updated anything has been successfully Burned by SD to a SYNET7LP hwver=11.2.0.6.

    Here is the new Home screen!

    $IMG_0415.JPG

    As suspected the SD card needs a specific format to be recognized upon boot. Here is view of the card partition.

    $Sd_image.JPG

    Details on how to create the bootable SD card so the update can be burned will follow once the excitement subsides!!!!
     
  13. st0ne

    st0ne Junior Member

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    I got the tool. and it want's an IUW file (*.ius) I don't have this...
    and there was no link to the update file the the threads you linked.
     
  14. st0ne

    st0ne Junior Member

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  15. st0ne

    st0ne Junior Member

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    I can't get the burn tool to SEE the SD card... the dropdown list is empty....
     

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