While programming lpc21isp adds garbage data at the end of program in flash memory

[swarzynski]

Hello!

While programming lpc21isp adds garbage data at the end of program in the flash memory. It is a problem when CRC value is calculated by the code from whole flash memory - CRC will differ when chip will be programmed by in example "Flash Magic" or "lpc21isp". Look at attached picture to see the details.

I would be glad if someone try to fix it or point me where to look for the function which is responsible for writing this data.

Regards

[jamesmarkchan]

@swarzynski did you ever restore this issue? This might explain some of the behavior we're seeing.

[cmcqueen]

I've been caught out by this bug in version 1.97. Is this bug still present?

[ArcolaJasper]

I see the same thing, only it crashes lpc21isp.

It's caused by lpc21isp not coping with files that are not a multiple of the block size.

In NxpDownload here: https://github.com/capiman/lpc21isp/blob/master/lpcprog.c#L1263

There is no check that the access to IspEnvironment->BinaryContent is less than IspEnvironment->BinaryLength so it over reads BinaryContent and you either end up flashing rubbish to the mcu, or crashing as you hit unallocated memory.

I added a check around it:

                              if ((Pos + Block * 45 + BlockOffset) > IspEnvironment->BinaryLength) {
                                printf("padding with 0\n");
                                c = 0;
                              } else {
                                c = IspEnvironment->BinaryContent[Pos + Block * 45 + BlockOffset];
                              }

That pads the last block with 0's. Not a real fix cos verifying still fails as well. But it stops it crashing for me at least.

(This is with an lpc1768)

[cmcqueen]

if ((Pos + Block * 45 + BlockOffset) > IspEnvironment->BinaryLength)

Should that > be >=?