Enable TMC in a nüvi 250W

**smokefree** · 20th January 2014, 02:31 PM

Originally Posted by ddabcd277

Just resell it and buy a new one rather than to kill it in an experiment.

Where's the educational part in that??

Originally Posted by Neil

<...> my attitude is 'wothehell'. Your unit is worth sweet-b*gger-all anyway.

We're on exactly the same wavelength!

I'm well prepared to sacrifice this unit for the sake of a good learning experience, but am confident it will be successful.

**smokefree** · 20th January 2014, 09:15 PM

Originally Posted by Neil

First do a backup of both your files and region 41, and do a hard reset.

Originally Posted by Neil

Make sure you do the backups and reset as in Post #28 [that's essential!]. If unsure of anything, please ask.

Followed all the steps, did the backup but forgot the hard reset. Result was a bricked device (frozen on the Garmin splash screen). I unbricked it (coincidentally I picked up some unbricking experience over the weekend on a nüvi 1390, which came in handy here...) and am now back at having a nüvi 250W again with nüvi 255WT capabilities.

Before going through the process again (but this time including the reset): by hard reset, do you mean touching and holding the right lower corner of the screen while booting up?

**Neil** · 20th January 2014, 10:00 PM

Yes exactly, hold lower RH cnr and start the unit. Unfortunately you cannot clear NV in 2 series as you can in 1xxx>, hard reset is all that can be done. I have never had a bricked 2x5W>465 when i've done hard resets though. Best to do it before and after flashing anything. If it happens again you may need to flash the 465 logo as well but usually 2x5W logo is fine.

**smokefree** · 21st January 2014, 09:41 PM

Well, followed all the steps, including backup and hard reset prior to any flashing. Still, immediately after flashing, the GPS ends up as a paper weight (frozen on the Garmin splash screen).

Converted it back to nüvi 250W with nüvi 255WT capabilities and tried one more time. Same result. Are you sure the 082701000420.rgn file from post #28 is correct?

**Neil** · 21st January 2014, 10:31 PM

I'm away from home at the moment and using a family member's computer. I have no easy way to check the rgn or remake it, but If you'd like a bit more practice you can make the kit yourself. Here's a walk thru:

Download both the 2x5W v7.60 and the 465 V4.20 firmware:

Code:

Please Login or Register to see the links

Open the 465 fw with [Only registered and activated users can see links. ] and save the fw_all.bin somewhere convenient. Then open the 265W fw and load the 465 fw_all.bin in place of the existing. Check the HWID override panel and set it to 0827 then save the combined firmware as 082701000420.rgn. If it still wont boot after flashing the re-made fw, open the hybrid rgn again with RGN_Tool and add the 465 logo into the third field. Save again as 082701000420.rgn and try again.

Nuvi 465 logo.bin:

Spoiler:

Don't forget to do the hard reset before and after each flashing.

**smokefree** · 22nd January 2014, 08:57 PM

Originally Posted by Neil

Open the 465 fw with [Only registered and activated users can see links. ] and save the fw_all.bin somewhere convenient. Then open the 265W fw and load the 465 fw_all.bin in place of the existing. Check the HWID override panel and set it to 0827 then save the combined firmware as 082701000420.rgn.

I take it you mean the 250W fw. The MD5 checksum of the .rgn file created myself is identical to the one you provided. Therefore safe to say the .rgn file is OK. I therefore continued with the next instruction:

Originally Posted by Neil

If it still wont boot after flashing the re-made fw, open the hybrid rgn again with RGN_Tool and add the 465 logo into the third field. Save again as 082701000420.rgn and try again.
Don't forget to do the hard reset before and after each flashing.

Flashing the new .rgn file (including the 465 logo) failed. Just as the progress bar wants to start at 0%, the GPS unit terminates preboot mode. Result is a failed flash (not a bricked unit though). Tried few times, same result:

cxxd

Maybe worth giving the other method a try?

**Neil** · 23rd January 2014, 11:42 AM

The firmware for HWID 0827 models is the same whether the model is 250W with HWID 0827 as yours is, or any 2x5W [i.e. 205W/255W/265W] with HWID 0827. As my rgn in the original kit was made with 2x5W fw, and is identical with your rgn made with 250W 0827 that's conclusive evidence. If the hwid is the same so is the fw.

As the simple conversion with original boot bin doesn't work, i would be inclined to not do a full conversion using the complete 465 fw as you may irretrievably brick it. It may work to compress the 465 fw_all.bin and retain the hwid, but frankly i think you may be better to just be satisfied with your progress this far and not push your luck any further. Perhaps the SW guys might give some further advice and opinion, but i feel there might be some subtle differences between the 205W 0827 and the 2x5W 0827.

**smokefree** · 23rd January 2014, 12:06 PM

I checked where I had his 250W unit from. It turns out I got it from Garmin as a refurbished unit in exchange for another 250W which had been recalled due to a possible battery problem (see following link):

Code:

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That may explain why the 250W came with v7.60 FW. Not knowing what else may be non-standard about this unit, it may also explain why the simple conversion method does not work...

**smokefree** · 23rd January 2014, 12:33 PM

Originally Posted by Neil

<...> i feel there might be some subtle differences between the 205W 0827 and the 2x5W 0827.

You mean there might be some subtle differences between the 250W 0827 and the 2x5W 0827?

**Neil** · 23rd January 2014, 12:53 PM

Originally Posted by smokefree

I checked where I had his 250W unit from. It turns out I got it from Garmin as a refurbished unit in exchange for another 250W .................
That may explain why the 250W came with v7.60 FW. Not knowing what else may be non-standard about this unit, it may also explain why the simple conversion method does not work...

Well, it's not a 'non-standard' unit as such. Garmin actually sold a lot of these about four years ago quite intentionally 'crippled' 255W as 250W [see Post #2 re that info]. What's good about your experience is that we've proven that the logo was the thing which crippled it and that full 255W functions can be enabled by flashing the 2x5W logo.

Originally Posted by smokefree

You mean there might be some subtle differences between the 250W 0827 and the 2x5W 0827?

Yep. I did mean 250W not 205W. Not sure if i should blame 2-finger typing, a second glass of Shiraz or advancing senility .....