CAVE CV1000 U2 repair tool u2_compare

[alamone]

Hi everyone, I was working on fixing a user's CV1000 board and developed this tool (https://github.com/alamone/u2_compare) to help diagnose and fix the graphics issues on the PCB.

It compares a U2 dump with a known good U2 (such as from MAME rom set), relocates any identified bad/corrupt assets to empty NAND blocks, and generates new blocks for writing to the PCB via JTAG using buffi's tools (https://github.com/buffis/cv1k_research). This way, you only need to erase and write a few NAND blocks instead of having to erase and write the entire NAND or desoldering & replacing the entire NAND chip.

As you might be aware, NAND flash can develop data corruption over time, which is normally handled by error correction, but CAVE did not implement any error correction at all in their code, which is why CV1000 PCBs can develop graphical glitches. Hopefully this tool will be useful for fixing these type of errors.

[thchardcore]

Very cool work. Thank you for sharing.

[PC Engine Fan X!]

So this tool would apply to the CV1000 pcbs of Ibara/Ibara Kuro all the way down to DDP-SDOJ then?

I've noticed that the RTC of a typical Ibara pcb will show up at a few minutes past 12:00 am (if the CR2035 battery that powers the RTC functionality is already dead to begin with) during a demo stage run and keep occurring upon being powered up for the day until it's properly replaced with a brand new battery. I've had a dead CR2035 battery issue/situation on my Ibara pcb occur one time. I'm not sure what the average lifespan of a new CR2035 battery installed on those early CV1000 pcbs would be. Of course, this is part of general maintenance/upkeep with those early production CV1000 pcbs nowadays.

PC Engine Fan X! ^_~

[alamone]

The tool will work with any CV1000 PCB including B and D variants, as both use the same type of NAND flash for U2.