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I seem to be getting at least two unsolicited questions a day from people who have inadvertently bricked their Eken M001/M002/M003 or Flytouch/noname tablets . So here’s a quick post with what I know about unbricking a wm8505 apad tablets.

You should also try slatedroid, and hassle whoever is making custom firmwares to remove the unnecessary bootloader reflash steps. These dangerous reflashes are what is causing so many tablets to brick in the first place.

Also, always plug your tablet in to the charger when flashing. Never unplug it or turn it off while it’s flashing, even if you’re accidentally flashing it twice. Seriously, people.

Bootloaders

WM8505 tablets have a pre-bootloader called W-Load, then a bootloader called u-boot, then the main OS boots.

U-boot will read a custom boot script from a file “script/scriptcmd” on an SD card, if it is present. This is how upgrades and reflashes work. U-boot is also capable of interacting with the user via the built-in 3.3v serial port, if you solder some wires to it.

Stuck on the ‘Android Logo’ boot screen

This is the first screen, which also says “Kernel Version X.Y.Z” and “SDK Version X.Y.Z.”. This screen is put up by u-boot.

If you’re stuck on this screen then u-boot is loading, which is a good sign. If putting in an SD card with an upgrade script does not work, then it may be broken in some other way. You may be able to connect a serial cable and interact directly with u-boot to issue commands.

Before you bother with the serial cable, make very sure you have formatted your SD card correctly (FAT32) . Try reformatting and re-copying all the files to the SD card, and then try using a different SD card. Various people have reported that only SD cards 2Gb or smaller work reliably.
Stuck on the ‘Android’ “shimmer” boot screen

If you’re stuck on the next boot screen (the text ‘Android’ that shimmers back and forth) then Android has started loading but is crashing. Reflash via the SD card.
Blank screen

If you have a totally blank screen then this is a much worse sign. In my experience, I’ve seen three possible things:

If the red power light blinks on when you press Power but then immediately goes out

Then you have a fault in your power circuit on the board. In my Eken, I can still make it boot if I take the back off and heat up the board with a heat gun (hair dryer would also work.)

If the red power light stays on and eventually you hear the ‘ding’ startup sound

(Instead of the ‘ding’, another sign is if you can connect it to your computer via USB.)

Then your Eken is working but your LCD panel is not. It might be broken, or it might be a bad connection. I’ve had luck pressing (lightly) around the edges of the screen.

If the red power light stays on but you don’t eventually hear any ‘ding’ startup sound

Then your Eken is probably stuck either loading W-load or u-boot. There are some anecdotal reports that these boards will still take a normal SD card based update, so try some different firmwares via SD card as a first step.

If that doesn’t work then you probably have a brick. The only way from here would be to reflash directly or via JTAG, and none has found a JTAG pinout on these boards. You can connect the serial port to be 100% sure, but I wouldn’t hold my breath.

Update: unbricking wm8505 via JTAG. Apparently this is for newer revision boards, where the JTAG pinout is broken out and clearly labelled.


I have none of the above

If you have different symptoms, feel free to post in the comments.

Post a Comment Blogger

  1. di ko din magets.. Kasi anung serial cable gagamitin? Then san po sya ilalagay..? Sorry po di ko talaga magetz

    ReplyDelete
  2. yung sakin ganito, sabi sa bootloader din daw nagkatopak. bale pag ioon ko yung apad, steady sa green light, tapos pag short press ulit sa power button mag off yung light. bale parang nag on off ung light kung pipindut pindutin mo yung power button. panu yun. O_o help naman.

    ReplyDelete
  3. hello hideki, you can try to fully discharge it then recharge before reflashing with a different known working rom for your apad:

    If the red power light stays on but you don’t eventually hear any ‘ding’ startup sound

    Then your Eken is probably stuck either loading W-load or u-boot. There are some anecdotal reports that these boards will still take a normal SD card based update, so try some different firmwares via SD card as a first step.

    ReplyDelete
  4. My Tablet won't boot up from SD card. When I power it up it displays the android logo in Green and then changes to android logo in White and then back to Green on and on. Can you help me?

    ReplyDelete
  5. what is your tablet sir, wm8650 or wm8505? -admin

    ReplyDelete
  6. I´ve got a bricked yarvik tab 210 here on the table, it won´t boot anymore - have you got any bright ideas, how to unbrick it - take your time to think, it ain´t my tablet...

    ReplyDelete
  7. Hey guys! I'm a bit frustrated on what had happened to my APAD. W8505 was written on it' s chipset. Whenever I turn the power on, it was stuck on black screen, a total black. What will I do? Btw, it is a Blue Led. Thanks. I'm a Filipino. You can talk to me in our language if you sure do know.

    ReplyDelete
  8. Hey guys! I'm a bit frustrated on what had happened to my APAD. W8505 was written on it' s chipset. Whenever I turn the power on, it was stuck on black screen, a total black. What will I do? Btw, it is a Blue Led. Thanks. I'm a Filipino. You can talk to me in our language if you sure do know.

    ReplyDelete
  9. Mine boots then continues to main screen then dings and powering off automatically, wm8505 chipset, it won't boot on SD.

    ReplyDelete

 
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