Fixing bricked Acer A500/A501 tablets with data errors, only booting in APX mode

When using nvflash or APX Tool to repartition an Acer A500/A501, some people get data errors, and assume their device is bricked, and is good only for parts.

For example, the command:

nvflash --bct flash.bct --setbct --odmdata 0x100c0105 --configfile flash.cfg --create --bl bootloader.bin --sbk 0x... 0x... 0x... 0x... --go

Will output:

failed executing command 11 NvError 0x120002
command failure: create failed (bad data)
bootloader status: failed to create the partition (code: 10) message: nverror:0x3 (0x3) flags: 0

Other commands may output something like this:

failed executing command 12 NvError 0x120002
command failure: create failed (bad data)
bootloader status: fatal failure to read / write to mass storage (code: 9) message: nverror:0x8 (0x19000008) flags: 0

The common theme is "bad data", indicating an error when trying to read or write to the flash storage on the device.

I encountered this same error on my Acer A500 tablet, and was able to fix it. Since I am not particularly handy, but was able to do this, anyone can do it.

The fix is to use a heat gun to reflow the solder. Basically, this is heating a specific area on an electronic motherboard so the solder reaches melting temperatures, then leaving it to cool down. In the process, any bad contact should be fixed.

Here is a video describing how to do this for an iPhone suffering from WiFi issues.

The exact same technique applies to the Acer A500 or A501, but you only heat the flash storage chip, while protecting the other components.

Disassembling The Acer A500/A501

The steps to disassemble

1. Turn the tablet off, and using a thin blade (I used a pen knife), pry the sides and top and bottom edges of the tablet, so the back cover comes off.
2. Remove the screws and connectors of the battery.
3. Remove all the connectors, wires and ribbon cables going into the mother board.
4. Remove the camera from the motherboard

Identify the Flash Storage Chip

The chip in question, like other components on the motherboard, has a silver colored metal cover on it. You have to pry that open using a small screw driver.

To identify the chip, it will have either SanDisk or Samsung. It is on the underside near the largest connector going into the motherboard (the one that adjacent to the battery).

You can find it on the bottom-ish left-ish next to the screw hole in this picture. This is an A501, so it has a SIM card socket, which will not be on the A500 model. In the rest of the pictures, he says the chip is SanDisk. In my case it was Samsung.

Protect the Board Using Aluminum Foil

Wrap the entire motherboard in two layers of aluminium foil. Expose only the flash storage chip.

Attach a small piece of foil to the screw hole and place a very tiny piece of solder wire on it. This will act as our indicator for the right temperature where solder wire melts.

Make sure the small piece of foil does not fly away with the air from the heat gun.

Apply The Heat Gun

Put the protected motherboard on an old metal tray, propped up with something else that is metal too. Place all this on a surface that would not be damaged by heat. I used an old baking pan for this.

Now, using the heat gun set on high, apply the heated air to the chip, at about a fist's length away. Once you see the piece of solder melting, continue for 5 seconds, then turn the heat gun off.

Leave the motherboard to cool without touching or moving it for 15 minutes or so.

Now, assemble the tablet again and try using nvflash or AXTool. If you are lucky, the tablet will work again.

Comment below if this helped, or if you have hints and tips for anyone else.