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This means, the flash-chips could not be successfully erased.
Here the proces will be terminated.
If the erase was partial successful, you could end up with a not working cartridge-content.

Cause can be: bad contact in the cartridge slot (most likely), take it out, clean/blow, in again and retry.
Or, hope not, some issues with the hardware, either your atari or the cartridge itself.

But when it still boots, you are ok.
Just clean the slot/pcb edge and try again.

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ok, that is odd.

and you didn't flash the content already, i mean, this is your first and virgin re-programming.

can you upload a screenshot of the cartridge content as it is now?
so I know what you have.

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ok, the content of the CF-card, I don't know what Steve sends out.
but the flash-content (cartridge menu) looks legit.

so, if you can not flash the cartridge from any atari with a valid 512kb flash-file, there is an issue with the cartridge.

you could try and create a flashdisk (atr) to verify that the cartridge can not erase itself before re-programming.
if you can't create or know how to create one, here is one I did earlier.
viewtopic.php?p=14852#p14852
It's the myide_only #7 on disk.
You need to boot that using an serialbus-device.

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Great, thanks for the update.