I know how dead mt-card is right now. I own both gateway and mt-cards & I love my gateway but I also love how mt-card saves games. Originally mt-card 2.3(latest official update) supports only upto 9.4 emunand,but here's how you can update it further to 10.1 with eshop acess.
Original idea goes to Trexxprin at iso site,I am just simplifying the process.

1) Turn off your 3ds Wifi & update your MT-Card launcher.dat to 2.3.
2) Now boot by pressing L and then executing exploit to open MT-Card menu. Here format your emunand(Warning this will format your sd-card). You should now be left with a 4.x emunand.
3) Backup this emunand with emunand tool just in case.
4) Now with 3dnus download 9.4 & 10.1 official update files.

5) Now look for these 4 titiles in 9.4 folder 000400300000CE02,0004003000008F02,0004001000021000,0004001000021900 for US
0004003000009802,0004001000022900,000400300000D602,0004001000022000 for EUR

6) move these 4 titles out of 9.4 update folder & delete these 4 titles from 10.1 folder (if any).
7) With this done move the 10.1 folder to your 3ds sd card and install all the cias in it with Devmenu with L+R+A to install all cias. Reboot and again backup emunand just in case. You should now have 10.1 emunand in MT-card. make sure your wifi is still off.
8) But hold on we still need eshop acess since out of these 4 titles 2 belong to eshop.
9) We now need to spoof these 4 titles version no's to 10.1 so that system update skips them, as these 4 titles cause seems to cause issue for mt-card emunand support higher than 9.4.
10) Now spoof this 4 titles (according to your 3ds region) to a title version like 10.1 or higher. I used 10.1 btw from here http://yls8.mtheall.com/ninupdates/titlelist.php?sys=ctr&wiki=1
11)After spoofing the version install the 4 spoofed cias in 10.1 emunand with devmenu. Check for system updates and there should be none and eshop should work now.
If this didnt work you for you did something wrong. Restore your 10.1 emunand with emunand tool we backed up earlier and try again.


How to spoof the cia version?
In this case I am taking example of 0004001000021000.cia[US].
http://yls8.mtheall.com/ninupdates/titlelist.php?sys=ctr&wiki=1 shows that we have v8203 from 9.0 update and we need to spoof it to atleast v9221(or more if you wish) which was in 9.6 update.
Open hxd and look for offset 00002F90 and then 0C-0D have your version no in hexadecimal. convert it decimal with this. In our case it is 20 0B with means 8203 in decimal and now again use decimal to hex to convert v9221 to hex which is 24 05 in hex. Now just overwrite 20 0B with 24 05 and save.
This completes the spoofing of version. Just repeat the steps for different cias

Alternatively you can also use 3dsnus for spoofing but I prefer the manual way.

Oh here's some proof of concept:
https://imgur.com/a/DpRHZ

 

[Deecy]

Hi
Got mt card emunand 10.3 but bravely second not work. Anyone have a way to make it work ?
Thank's

 

[Quicksilver88]

Hi
Got mt card emunand 10.3 but bravely second not work. Anyone have a way to make it work ?
Thank's

I think some of the newer games have been using sometime of Cartridge AP. I think SMT Devil survivor 2 was the first one. You might try getting a .cia version of Bravely install that and see if it will work.

 

[Deecy]

Yes with a 10.6.0-31E emunand the .cia work fine.

 

[Jojomato]

I don't understand how to spoof the cia files...
When I open it in hxd I can't find the offset 00002F90.
Is there a way to spoof the cia files with 3dsnus ?

Thanks !

 

[sneaker8650]

i updated my emunand to 10.6 aswell, but bravely second wont start. Older Games can be installed via cia without problems.

I would also like to try arm9loaderhax, but i did not touch my o3ds for months, still on 4.4 and i only used the mt-card. Could someone link me a tutorial, to install cfw ?

 

[Margen67]

i updated my emunand to 10.6 aswell, but bravely second wont start. Older Games can be installed via cia without problems.

I would also like to try arm9loaderhax, but i did not touch my o3ds for months, still on 4.4 and i only used the mt-card. Could someone link me a tutorial, to install cfw ?

https://github.com/Plailect/Guide/wiki/OTP-Info
There should also be guides for updating to 9.2 on GBATemp.

 

[Timburpton]

So this can work with 10.6 as well?

 

[Quicksilver88]

So this can work with 10.6 as well?

I actually just tried it with the recent 11.0U release and it works.

I pulled 11.0 from 3DNUS and got 9.4 from the iso site. I was able to deduce the proper hex values by just looking at the 2F90 field in the files that need to be fixed in the v11 update.

I then hex edited the 9.4 version of the files and followed the directions using devmenu.3ds from my MT card to do the .cia install. After the second reboot I did come up in the v11 emunand and I could log on to eshop.

Now here is the kicker though......it is really only a sort of fix in that you are still not going to be able to run newer content (using new 10+ keys I guess) from your MR card or your SD_Card. You will still have to install crypto/fw fixed versions of your games to run them with the MT_Card 2.3 launcher and this jacked up firmware.

So this would seem to have some limited value in that it does give you eshop/online access but it doesn't really 'fix' the problem of running newer un-patched games because essentially. Some newer games require updated firmware for online play so it may be useful for that but you will have to 'fix' the game to get it running to test.

So probably just going to leave the MT_Card at 9.4 and setup a second SD to use on this launch 3DS and use RxTools with the latest firmware. I really wish someone would update the MT_Card launcher to work with newer emunand. Given how little changes have been made to open CFW I suspect it would take someone who knows what they are doing less than an hour to update the launcher.dat

 

[Timburpton]

Cool, do you think that the launcher.dat will work with N3ds with a suitable entrypoint such as GW's OOT?

My understanding is that the OOT entry point triggers launcher.dat hence it should work.

After all, the MSET entry point also triggers both GW's launcher.dat and MT's launcher.dat.

 

[Quicksilver88]

Cool, do you think that the launcher.dat will work with N3ds with a suitable entrypoint such as GW's OOT?

My understanding is that the OOT entry point triggers launcher.dat hence it should work.

After all, the MSET entry point also triggers both GW's launcher.dat and MT's launcher.dat.

I don't think so because the MT_Launcher was based on GW 2.x which did not support 9.x yet. So only way I know of to use MT is with a 4.5 sysnand.

 

[BerT6801]

Does this still work..... not sure if it even matters since I can't get 3dNUS to see or download anything.... but still...I want my MT card back to working status for newer games