Re: GPSMAP 66 GPS Software 2.70
Posted: Thu Aug 29, 2019 5:16 pm
It’s 2.60 downloaded from the files section here.
The version info strings displayed in the about screen are meaningless, and could be changed to say anything of the same size.
The actual version number 0x0104 (decimal 260) reversed for correct endianness (0x0401) appears in the gcd file before the serial number 006B331300, and in a few other places, and is changed to 0x010F (decimal 271).
Then I recalculated the gcd file checksum, as must be done when any change is made to any gcd file, and that’s it.
The values that have been changed to 271 are the values that are checked for the next real version update.
Interesting because the unit firmware can be downgraded without doing any of this, and that’s always been the case.
It just doesn’t allow you to apply an update with the same device firmware as is already on the device,
but you can go forward or backwards (as far as device firmware is concerned).
The version info strings displayed in the about screen are meaningless, and could be changed to say anything of the same size.
The actual version number 0x0104 (decimal 260) reversed for correct endianness (0x0401) appears in the gcd file before the serial number 006B331300, and in a few other places, and is changed to 0x010F (decimal 271).
Then I recalculated the gcd file checksum, as must be done when any change is made to any gcd file, and that’s it.
The values that have been changed to 271 are the values that are checked for the next real version update.
Interesting because the unit firmware can be downgraded without doing any of this, and that’s always been the case.
It just doesn’t allow you to apply an update with the same device firmware as is already on the device,
but you can go forward or backwards (as far as device firmware is concerned).