M241 PLC Led Err blin, no usb or ethernet

[MistrzZen]

I have an M241 PLC with a blinking error LED. According to this document, I attempted to update it using an SD card, but the PLC didn’t read anything—only a single blink of the SD card LED occurred.

After a thorough inspection, including measuring on-board voltages and checking with a thermal camera, everything seemed fine. The current consumption of the main IC was around 300mA on a 1V power supply, which appeared normal.

As a next step, I reballed the main IC (Spear 680-2). After this, I was able to update the PLC via the SD card, but the device still wasn’t detected via USB (despite the driver being installed) or Ethernet, even when connected through a router.

I also reballed the DRAM and Micron memory IC, but this had no effect. My final attempt was to update the BIOS chip directly. After that, the Spear IC became visible via USB, but the PLC didn’t function correctly, as expected.

Has anyone encountered a similar issue and found a solution?

[asisnaira]

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@MistrzZen wrote:

I have an M241 PLC with a blinking error LED. According to this document, I attempted to update it using an SD card, but the PLC didn’t read anything—only a single blink of the SD card LED occurred.

After a thorough inspection, including measuring on-board voltages and checking with a thermal camera, everything seemed fine. The current consumption of the main IC was around 300mA on a 1V power supply, which appeared normal.

As a next step, I reballed the main IC (Spear 680-2). After this, I was able to update the PLC via the SD card, but the device still wasn’t detected via USB (despite the driver being installed) or Ethernet, even when connected through a router.

I also reballed the DRAM and Micron memory IC, but this had no effect. My final attempt was to update the BIOS chip directly. After that, the Spear IC became visible via USB, but the PLC didn’t function correctly, as expected.

Has anyone encountered a similar issue and found a solution?

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You’ve already taken several good steps, but the issue might still be with the main Spear IC or related components. Since reballing the ICs allowed the device to update but not fully work, it suggests potential deeper hardware issues with the Spear chip or memory

[MistrzZen]

From my point of view the spear is good becouse when i dump bios ic with firmware from sd card i think then bios firmware isnt comaptible and spear goes into boot mode so my first thought is corrupted bios, is it possible to recive it from support? Second thought is NAND chip if SLC is used that means about 100k of cycles so some bad sectors can be possible.