I hear what you're saying, but from an electronics standpoint, I don't see why being on a 1 file firmware would prevent the SPI NOR chip hack from working. As long as the 335 firmware supports the "recovery mode" that's shown in the video after you flash the SPI NOR chip, then I would think this would still work. Just my opinion though.Whats shown in the video might work for 2 File Firmware (up to/including 70.00.100), but I think anhnga mentioned, that the SPI NOR chip can not be used to fix problems with the 1 File Firmware (70.00.335 and higher).
All you're doing is changing the specific memory address of the chip to a value that gets it back into the recovery mode. Perhaps the latest version of firmware doesn't use that chip at all? That's possible, I just dont see why Mazda would get rid of the recovery mode from one version of FW to the next.