Deleting files should not result in a bootloop. Did you do anything else? Usually a bootloop is caused by the device trying to load a faulty file unsuccessfully. Because the device is powering off and on in an endless cycle it's harder to gain preboot and initiate a flash. Try this method:
  • Force device fully OFF by holding down the power button for an extended period, usually 10 - 30 seconds is required. Release button and don't press it again.
  • Load cure firmware to Updater.exe (try quickcure3 first, it usually works)
  • Leave Updater's GUI visible on your desktop, select 'USB Device' radio button
  • Connect a suitable USB cable directly to a REAR USB2 port of PC without a hub, don't use a front port or USB3 port
  • While watching the window next to USB Device, hold the nuvi screen's upper LH corner firmly with your left thumb and plug the cable into nuvi's USB socket which will power it on
  • IMMEDIATELY you see the device details appear in the window on Updater's GUI click 'OK' or just hit the enter key on your PC KB
  • Keep firm steady pressure on the screen until the flash finishes or at least until 'Loader' or 'Software Loading' appears on device screen
  • If successful the device will stick on the logo splash screen and you'll have Mass Storage Mode available

If you miss the very short opportunity time to initiate the flash, start again from the top with device off again. Once the flash is started the device won't drop preboot mode.