NOTE:
(1) Many units can be put into pre-boot mode by holding the screen in the correct spot and plugging in the mini/microUSB with the lead already connected to the PC [preferably a rear port]. This method does not require the device to be turned on by the on/off button.
(2) When pre-boot is accessed by holding the screen and powering by on/off switch if flashing is not commenced quickly using updater.exe then the nuvi after a short period will move from pre-boot mode to the calibration screen and then boot normally [if not bricked]. If by holding screen and powered on by connecting to PC it will eventually go to Mass Storage Mode [if not bricked].
(3) If the nuvi is not bricked, for some series entering into the hidden menu by pressing and holding the battery symbol and then connecting the PC USB cable will access pre-boot indefinitely allowing a leisurely flash.Pre-Boot for
nuvi 2xx & 2xxW series. 200(W), 250(W), 260(W), 270:

1. Turn off the navigator.
2. Press and hold the upper left corner of the screen.
3. Click and hold down the power button.
Pre-Boot for
nuvi 2x5 & 2x5W series. 205(W), 215(W), 255(W), 265(W), 275, 285W & nuvi 465:
1. Turn off the navigator.
2. Press the upper left corner of the screen.
3. Start the navigator
Note: In older versions of the firmware and in some versions of devices is the same than in series 200, 200W.
Pre-Boot for
nuvi 7x0, 7x5:1.Turn off nuvi.
2. Hold finger on the upper
right corner of the screen [it's been reported that some units need be held in centre of screen].
3. Slide to Power on,
slide to lock, and quickly Insert USB cable."
Note: 7 Series nuvi units can be notoriously difficult to flash using the above method to enter preboot mode. Only 10 seconds of preboot time is available before the unit moves out of preboot to the calibration screen so it's imperative that flashing commences quickly. For some tips and quirks read Posts #15 through to #24, in particular Post #23 as you may have to additionally move the power slide back to the middle [neutral] position after the flash starts for it to complete. If the unit's not bricked, the easiest way is to press and hold the battery symbol on the main page for ~6 seconds to enter the hidden menu because then the unit is in preboot and will maintain it so flashing can be done more leisurely.Pre-Boot for
nuvi 3x0 and 6x0:1. Turn off the navigator.
2. Click and hold down the power button.
Pre-Boot for
nuvi 5x0 [and zumo 2x0]:1. Turn off the navigator.
2. Click and hold the upper left corner of the screen.
3. Click and hold down the power button.
Pre-Boot for
nuvi 11x0, 12x0, 13x0, 14x0:1. Turn off the navigator.
2. Press the upper left corner of the screen.
3. Turn on the navigator still holding the upper left corner of the screen

Pre-Boot for
nuvi 30, 4x, 5x:1. Turn off the navigator.
2. Press the upper left corner of the screen.
3. Turn on the navigator still holding the upper left corner of the screen
Pre-Boot for
nuvi 2xx0 [including dezl 560]:1. Turn off the navigator.
2. Press the upper left corner of the screen.
3. Turn on the navigator still holding the upper left corner of the screen
Pre-Boot for
nuvi 2xx5:1. Turn off the navigator.
2. Press the upper left corner of the screen.
3. Turn on the navigator still holding the upper left corner of the screen.
Pre-Boot for
nuvi 34x0, 35x0, 37x0:1. Turn off the navigator.
2. Turn on the navigator and immediately press in the middle left of the screen for 37x0/35x0, i.e. just
above the letter "G" of the Garmin logo [~40mm in, 25 mm down for 4.3" screen 37x0],
on the "G" [~40 x 40mm] for 34x0. (Using your left
thumb for holding both on and over should work for both series). Keep on holding the screen. 37x0 shown below:

Pre-boot for
DriveAssist 50 could also apply to Drive & DriveSmart:[/b]
1.Turn off the device
2. Power on [preferably by making USB connection to PC]
3. When GARMIN logo appears quickly press above and between letters G and A:

Pre-Boot for
DriveLuxe 50:1. Turn off the navigator.
2. Press the upper left corner of the screen.
3. Turn on the navigator still holding the upper left corner of the screen.
Pre-Boot for
nuvi 5000:1. Have the navigator OFF.
2. Press the upper left corner of the screen.
3. Connect via USB to PC while still holding the upper left corner of the screen.
NOTE: nuvi 5000 lacks an internal battery so cannot power on without an external source.
Pre-Boot for
zumo 660:1. Turn off the navigator.
2. Press the LOWER left corner of the screen .
3. Turn on the navigator still holding the lower left corner of the screen + power button.