IOB6120 is alive and talking to the flash, debugging continues

HI-Z TESTS DON'T SPOT OBVIOUS FAKE CHIPS BUT DOES FIND SHORT ON FLASH

I checked all the data pins of the four SRAM and one flash chips, looking for pins that were near ground or VCC rather than high impedance. The SRAM chips looked fine by this measure, so I moved on to the flash. It was while I checked the data pins that I found one shorted to VCC, which was an adjacent pin. 

I looked under the microscope and really couldn't see the short, which seemed to be a bridge up under the body where I couldn't see it. However, some solder wick to the rescue and soon I had the bridge gone. 

WITH SHORT REMOVED, SBC6120 COMES UP WITH IOB6120 IN PLACE

Previously, with the IOB board installed, the SBC6120 stopped in the memory test phase of initialization. Now, it proceeded through to the end and started up the monitor program that communicates over the console terminal. This is very good news.

ISSUE FLASH LOAD COMMAND AND IT SEES THE CHIP

With the IOB not installed, issuing a FL command receives an immediate response that flash is not installed. Now, when I typed FL the response was a question - "overwrite flash?" Again a very good indication. 

At this point, one would set up the terminal program to send lines of text to the console, waiting for the prompt ':' before sending each line. I don't have a terminal program with this capability, just PuTTY and the Arduino Serial Monitor. 

MANUALLY SENDING LINES TO FLASH LOAD

I decided to do a copy and paste line by line from the text file into the PuTTY window as a workaround. I transmitted each line until I got to the end of one block, where the FL command expects to receive a checksum value which it compares to the calculated checksum of the lines previously sent. If that compares successfully, it writes the block to flash then reads text lines for the next block.

WHEN FIRST BLOCK WRITE IS ATTEMPTED, I/O ERROR 1050 IS REPORTED

As soon as I sent the checksum, the load aborted with a message that it received Input Output Error 1050. I suspect this is a compatibility issue because I am using a different flash chip than originally specified. I will do some research into this error and then figure out how to resolve it. This may involve creating my own method of writing to the flash chip or a modification to the SBC6120 firmware to alter its flash write process.