I downloaded GMap Tool and gimgunlock. I ran the img file (called mapsupp.img) from my sd card (about 4 Gb) over the gimgunlock icon and there was a flash of numbers. I then opened GMap Tool and put the .img file in it.
It didn't appear to be the same format as in your instructions, but there was not an L to be seen.
I put the sd card in my 2689 and started it. 'Can't unlock maps' appeared on my screen. I can see the .img file in a Garmin folder as a separate drive on my pc.
G
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