Hand tools and fabrication machines
It is well known Garmin company is so greedy that makes customers to buy proprietory USB cable to charge their GPS devices. This should be punished.
In order to use any USB cable pins 4 and 5 of USB jack must be connected by 18K resistor. There were 2 publications on how to do this:
1) Insert resistor into mini-USB plug
2) Install tiny SMD resistor inside cradle directly between pins 4 and 5 of USB jack, very nice and detailed article:
Fortunately, a cradle for Nuvi 2797 allows to use more comfortable regular resistor and easy soldering. A bit of Dremel work is required though.
So this is a cradle:
Resistor must be installed between pins 4 of USB jack (which in normal USB cable is not used) and pin 5 which is ground. Turned out that pin 4 of USB is connected to the 5th contact from the right of cradle contacts grid, while contacts 1 and 4 from the left are connected to the ground. So you need to solder a resistor between contact 5(from right) and contact 4 (or 1) from left.
The first (an only) trick is to open the cradle.
With yet another lousy attempt to make their stuff 'untouchable' and difficult to disassemble greedy Garmin uses tiny screws with quite rare Torx T5 heads.
You will need this:
This is how opened cradle with soldered resistor looks:
A close-up of soldered resistor:
You will need to remove part of a plastic grid from the inside of cradle cover in order to prepare a space for resistor. Dremel and some carving bit will do that easily: