Hi, I just need to share this information, as I believe I finally found a way to disable write protection.
My player: "auro sound zx18" mp735c-stl 1.2 with memory chip: SAMSUNG 625 K9WAG08U1A PCB0 FHEE87P1
I was testing different firmware to try and find one that suited my mp4 player (still is), and suddenly the player was write protected for apparently no reason. I have no idea why it was.
I tried different settings in the computer, and I tried looking for a lock switch on the device to no avail. Nothing worked. I then tried the following, and VOILA! the device was recognized as an ADFU device, and the write protection was disabled. I could now upload the firmware, and afterwards, I could format the device and put files on it.
WARNING! This is a last resort solution. You can seriously harm your device if you try this, or maybe even your USB port, but I took the risk as the device was worth nothing to me if it was write protected. I take no responsibility for what you choose to do with your stuff.
1. Look up what memory chip you have. Mine was the SAMSUNG K9WAG08U1A.
2. Find a matching datasheet, and look for the pin called WE (Write Enable). For me that was pin 18, 7 from left bottom.
3. While the device is connected to the PC and turned on, connect GND to that pin with a wire, and the device will restart. Be careful not to short anything else.
4. If nothing happens, restart the device by turning it off and on.
Now the device should be recognized as an ADFU device, and you can once again upload your firmware to the device.
I tried this once and it worked like a charm. Please post your result below to let others know if this is a worthwhile solution.
How I disabled write protection on my mp4 player
