Large Full-screen JCV File Changes?

...thanks for your help with the large .jcv problem.

Maybe that’s why a lot of guys here say that they need a microSD card before they can install the new map. It’s huge. Possible that Garmin decided to add every junction in the US and Canada for us?

...a 16 GB card.

I just don't know if the nuvi 1450 will get confused by so many .jcv files.

The problem is not the micro SD card as that is easily solvable. The problem is with the multiple JVC files. How did that happen? I suspect that I should keep the D3060350A.jcv and delete the other three files but I'll wait to see if Garmin has any ideas.

I wonder if other people that natively download the large full-screen JVC file with their update are having the same issue? It will be interesting to hear Garmin's explanation as well if they will reply. This was my first ever contact with Garmin support.

Mcginkleschmidt, we anxiously await a resolution to this. It certainly sounds like an error on Garmin's part. Are the file dates for each all the same, the day the map was just updated?

The closest thing I have age-wise to your 775T is a 2460 and its single jcv file is 499,284KB. For the 3597, the file is identical: 499,284KB. Since mine are split-screen JVs, it would equate to your roughly 800,000KB full-screen JV in a JCV file. For what it's worth, the new tiny jcv file for the nuvi 855 is a mere 25,973KB and is D3153350A.jcv.

One issue that your 775T has that could complicate things is that the 775T came with maps of North America and Europe so maybe some of your several jcv files are from across the Pond.

My 1390T that I have has the same file as the 775T above. D3153350A.jcv and 25,973KB. Most likely a screwup on Garmin's behalf and we only need the D3153350A.

All four JCV files have the same date 3/17/2021 with slightly different times as the download times for each of the four JCV files vary by a few minutes.

I got the same thing on my nuvi 755 download. I suspect these are for different map region downloads and you are only supposed to get one of the files based on your device model and region downloaded. I am guessing Garmin has an error in their download manifest and are incorrectly giving you all the available JCV variants. I ended up deleting all the files except the normally named D3060350A.jcv . Copied it to my nuvi 855 and tested it on a couple of long routes ... seems to be working OK for junction views. I haven't been able to actually test my old nuvi 755 because my daughter has it and with COVID we haven't been able to get together for over a year. When she gets her vaccine, I will get the old 755 back from her and test it. (Note: I was able to do the 755T map download and get the 4 JCV files with cloning, but can't actually test it on the 755T until I can get my hands on it again. But like I said, D3060350A.jcv works OK on the 855)

Thanks alandb for the feedback about your experience with the Large JCV file download.

We have seen this in the past with the Large JCV file, where different people got slightly different size files with different names for the same map version, although any one user only got one of the variants. I don't remember all the details now, but I don't think we ever came up with a definitive explanation. I do recall that there was some speculation that a zumo user was getting a JCV file with a different name and slightly different size than a nuvi user. I think this was discussed 2 or 3 years ago, but don't know if it was this forum or a different one.

Perhaps.. you get multiple files to suit those that opt to get only partial maps. Because the "map" now covers parking lots and a lot more green spaces (the only difference I have seen so far) it is way bigger than the various models can store.. without adding memory.

I heard back from Garmin Support about the change from 1 to 4 JCV files. The following was their response:

"As more information keeps getting added to the mapping, the files are going to continue to grow in size. The JCV files show images of major highways, exits, and merge lanes upcoming on a route. We continue to add more and more of these images to our updates and they are split up into regions to help make the device faster. It doesn't have to read the entire 2.6GB file to get the image it needs when they are broken up into several files. There is nothing wrong with the update, this is just part of increasing the abilities of navigation units.”

I edited my Large JCV File Download for 2022.10 post with links to allow downloads of either the single or all four JCV files.

OK, I can see how this explanation could be correct. But think about it. Why would Garmin be spending an inordinate amount of effort to maximize the benefit of owners of the truly ancient nuvi 765T (or possibly all 7x5 models, as well as the zumo 6xx series) which are the only models offered the Large JCV File(s?) with a new map update while offering just a single under 500,000KB file for the top of the line nuvis and the current upper-level Drive models?

It would take a lot of effort and probably not worth it for you with the multiple files totaling over 2,600,000KB to selectively run routes with all files present vs just the one vs some combo of files, then see if any additional Junction Views appear.

You're right, it defies logic and it is hard to believe Garmin has increased the various road images by a factor of x 3.2. Time will tell I suppose.

I don't buy it. I think the Garmin rep didn't know the answer and made something up. I'd be glad to be proven wrong, but for now, that's my opinion.

If I can get access to my old 755T again, I will try to install all 4 files on SD, then look at the hidden diagnostic menu to see if they all show up. I am guessing only one of the files will be posted.

I agree with what others have said about the additional files. It makes absolutely no sense to do an update on a old unit like the 755T and not have the same updates (files/file size) for the newer units like my Drivesmart 55. Probably an programming error on Garmin's part but they won't admit it. I ran on the single file on my 1390T for the last couple of days and it works perfectly fine. I added the 3 extra files this afternoon and will see if it makes any difference. Wouldn't fit on my 8GB microSD and had to upgrade to a 16 GB one. It will be interesting to see what the JCV looks like in the next map update.

THANKS Mcginkleschmidt for uploading the full set of files and the link.