Hello,
I have not completely tested the PSR-800, so I am not sure everything works. Scan and Limit Search works. Battery charging is a known problem. I can easily flash it back to the correct firmware, but I like being able to create objects on the scanner.
It is highly unlikely that NXDN will be released for the PSR-800, Pro-668, and WS-1080/1088 for the simple reason there is not much flash space left. Flash space in the M16c processor grows down from the top of memory, so firmware for the 512KB flash processor starts in flash memory space that does not exist in the 384KB flash processor used in the PSR-800.
GRE implemented a method that prevents loading the wrong firmware in the scanner by changing the data so it fails the checksum check. You can not directly flash the WS-1080 firmware image into another scanner as the bootloader will incorrectly change the firmware data, the checksum check will fail, and the scanner will end up in firmware update mode. It is not a simple matter of changing only a few bytes.
Another likely reason has to do with later changes to the ECPA. Scanner/Receiver manufacturers got Congress very upset with the easily reversable implementations used to block the 800 MHz cellular range. In some receivers it was just a matter of clipping or adding a diode. GRE had to make sure that the firmware was not easily modifiable, and unblocked versions of firmware could not be loaded (I also have a PSR-600 and there was a Canadian version of the firmware). This maybe the reason the file formats of the programming files EZ-SCAN loads on the scanner are not published, as it could be used as a backdoor to add cellular frequencies.
The firmware file starts with a byte that seems to indicate the platform the firmware is meant for. Just changing the first byte of the file did not work, so it is not likely used by the bootloader to decode the file.
FB PSR-600 BL 1.1
F5 PSR-600 Canadian
F3 PSR-600 BL 1.4
EE PSR-800
E6 WS-1080
E4 PRO-668
The next three bytes are the size of the image. The next two bytes appear to be a checksum and is also where the exclusive-oring of the data starts. The image follows and seems to be a flat binary image starting at the beginning of flash space.
Since I used modified copyrighted programs and tools, I cannot distribute the modified firmware. I would have to write a program from scratch that downloads the WS-1080 firmware, converts it on the fly, and writes it to the other scanners. I am not sure I want the support headaches.
73 Eric