If you downgrade to 2.1.0 on a 2DS or New 3DS and left Wireless Communication off, you can re-enable the wireless by removing the battery and unplugging the charger for several seconds then booting back up.
If you've been using the New 3DS's microSD Management to transfer files to your SD card, this will no longer work on 2.1.0. Ensure you have a microSD card reader available before proceeding.
Your device may not show your installed games after the ctrtransfer. This is due to the tickets being removed by the transfer, which is why you back them up. They will be restored at the end of the guide.
{: .notice--info}
**For now, connecting your device to the internet is REQUIRED to continue after the 2.1.0 ctrtransfer.**
{: .notice--warning}
**Disable the parental controls of your device before doing the 2.1.0 ctrtransfer. If you do not know the password, see [this](https://mkey.salthax.org/) site.**
{: .notice--warning}
**Performing a ctrtransfer will remove all user-installed tickets from the device until a backup is restored. Under NO CIRCUMSTANCES should you skip creating a backup!**
{: .notice--danger}
**Never format a 2DS while on a version <6.0.0 or you will be unable to complete initial setup and will BRICK!**
{: .notice--danger}
**Never update a New 3DS running 2.1.0 (an Old 3DS firmware) or you will BRICK! You MUST restore a NAND backup or ctrtransfer back to standard New 3DS firmware first!**
{: .notice--danger}
#### Overview of steps
In this section, we will be flashing your console's [CTRNAND](https://www.3dbrew.org/wiki/Flash_Filesystem#CTR_partition) partition to 2.1.0 in order to take advantage of an oversight in 2.1.0 for the purpose of extracting the [OTP](https://www.3dbrew.org/wiki/OTP_Registers) unique to your console. This OTP file is required to install arm9loaderhax, and **cannot** be shared with other consoles.
This is accomplished by [installing a premade ctrtransfer image](https://www.reddit.com/r/3dshacks/comments/4zhe4a/) containing 2.1.0, copying your console specific files (such as `moveable.sed` and `SecureInfo_A`) to it, then fixing the title databases.
#### What you need
* You will need to have booted into Decrypt9
* The 2.1.0 ctrtransfer image for your device and region
*(if your device is not from one of these regions, just pick one)*:
+ [New 3DS or Old 3DS or 2DS 2.1.0 - EUR - ctrtransfer](magnet:?xt=urn:btih:89acc9c1b488b8b38251de0ddf07975d6bd354a1&dn=2.1.0-4E%5Fctrtransfer%5Fo3ds.zip&tr=udp%3A%2F%2Ftracker.coppersurfer.tk%3A6969%2Fannounce&tr=udp%3A%2F%2Ftracker.opentrackr.org%3A1337%2Fannounce&tr=http%3A%2F%2Ftracker.opentrackr.org%3A1337%2Fannounce&tr=udp%3A%2F%2Fzer0day.ch%3A1337%2Fannounce&tr=udp%3A%2F%2Ftracker.leechers-paradise.org%3A6969%2Fannounce&tr=http%3A%2F%2Fexplodie.org%3A6969%2Fannounce&tr=udp%3A%2F%2Fexplodie.org%3A6969%2Fannounce&tr=udp%3A%2F%2F9.rarbg.com%3A2710%2Fannounce&tr=udp%3A%2F%2Fp4p.arenabg.com%3A1337%2Fannounce&tr=http%3A%2F%2Fp4p.arenabg.com%3A1337%2Fannounce&tr=udp%3A%2F%2Ftracker.aletorrenty.pl%3A2710%2Fannounce&tr=http%3A%2F%2Ftracker.aletorrenty.pl%3A2710%2Fannounce&tr=http%3A%2F%2Ftracker1.wasabii.com.tw%3A6969%2Fannounce&tr=http%3A%2F%2Ftracker.baravik.org%3A6970%2Fannounce&tr=http%3A%2F%2Ftracker.tfile.me%2Fannounce&tr=udp%3A%2F%2Ftorrent.gresille.org%3A80%2Fannounce&tr=http%3A%2F%2Ftorrent.gresille.org%2Fannounce&tr=udp%3A%2F%2Ftracker.yoshi210.com%3A6969%2Fannounce&tr=udp%3A%2F%2Ftracker.tiny-vps.com%3A6969%2Fannounce&tr=udp%3A%2F%2Ftracker.filetracker.pl%3A8089%2Fannounce)
+ [New 3DS or Old 3DS or 2DS 2.1.0 - JPN - ctrtransfer](magnet:?xt=urn:btih:3dbb9c9c85a33c6242f424dcbaebcacdd8a5912b&dn=2.1.0-4J%5Fctrtransfer%5Fo3ds.zip&tr=udp%3A%2F%2Ftracker.coppersurfer.tk%3A6969%2Fannounce&tr=udp%3A%2F%2Ftracker.opentrackr.org%3A1337%2Fannounce&tr=http%3A%2F%2Ftracker.opentrackr.org%3A1337%2Fannounce&tr=udp%3A%2F%2Fzer0day.ch%3A1337%2Fannounce&tr=udp%3A%2F%2Ftracker.leechers-paradise.org%3A6969%2Fannounce&tr=http%3A%2F%2Fexplodie.org%3A6969%2Fannounce&tr=udp%3A%2F%2Fexplodie.org%3A6969%2Fannounce&tr=udp%3A%2F%2F9.rarbg.com%3A2710%2Fannounce&tr=udp%3A%2F%2Fp4p.arenabg.com%3A1337%2Fannounce&tr=http%3A%2F%2Fp4p.arenabg.com%3A1337%2Fannounce&tr=udp%3A%2F%2Ftracker.aletorrenty.pl%3A2710%2Fannounce&tr=http%3A%2F%2Ftracker.aletorrenty.pl%3A2710%2Fannounce&tr=http%3A%2F%2Ftracker1.wasabii.com.tw%3A6969%2Fannounce&tr=http%3A%2F%2Ftracker.baravik.org%3A6970%2Fannounce&tr=http%3A%2F%2Ftracker.tfile.me%2Fannounce&tr=udp%3A%2F%2Ftorrent.gresille.org%3A80%2Fannounce&tr=http%3A%2F%2Ftorrent.gresille.org%2Fannounce&tr=udp%3A%2F%2Ftracker.yoshi210.com%3A6969%2Fannounce&tr=udp%3A%2F%2Ftracker.tiny-vps.com%3A6969%2Fannounce&tr=udp%3A%2F%2Ftracker.filetracker.pl%3A8089%2Fannounce)
+ [New 3DS or Old 3DS or 2DS 2.1.0 - USA - ctrtransfer](magnet:?xt=urn:btih:1609ce9ee7b0ed9b6dea0b3e7cca4fc52dad6ff4&dn=2.1.0-4U%5Fctrtransfer%5Fo3ds.zip&tr=udp%3A%2F%2Ftracker.coppersurfer.tk%3A6969%2Fannounce&tr=udp%3A%2F%2Ftracker.opentrackr.org%3A1337%2Fannounce&tr=http%3A%2F%2Ftracker.opentrackr.org%3A1337%2Fannounce&tr=udp%3A%2F%2Fzer0day.ch%3A1337%2Fannounce&tr=udp%3A%2F%2Ftracker.leechers-paradise.org%3A6969%2Fannounce&tr=http%3A%2F%2Fexplodie.org%3A6969%2Fannounce&tr=udp%3A%2F%2Fexplodie.org%3A6969%2Fannounce&tr=udp%3A%2F%2F9.rarbg.com%3A2710%2Fannounce&tr=udp%3A%2F%2Fp4p.arenabg.com%3A1337%2Fannounce&tr=http%3A%2F%2Fp4p.arenabg.com%3A1337%2Fannounce&tr=udp%3A%2F%2Ftracker.aletorrenty.pl%3A2710%2Fannounce&tr=http%3A%2F%2Ftracker.aletorrenty.pl%3A2710%2Fannounce&tr=http%3A%2F%2Ftracker1.wasabii.com.tw%3A6969%2Fannounce&tr=http%3A%2F%2Ftracker.baravik.org%3A6970%2Fannounce&tr=http%3A%2F%2Ftracker.tfile.me%2Fannounce&tr=udp%3A%2F%2Ftorrent.gresille.org%3A80%2Fannounce&tr=http%3A%2F%2Ftorrent.gresille.org%2Fannounce&tr=udp%3A%2F%2Ftracker.yoshi210.com%3A6969%2Fannounce&tr=udp%3A%2F%2Ftracker.tiny-vps.com%3A6969%2Fannounce&tr=udp%3A%2F%2Ftracker.filetracker.pl%3A8089%2Fannounce)
#### Instructions
##### Section I - Prep work
You should be in Decrypt9 for these steps.
1. Press (Select) on the main menu to eject your SD card, then put it in your computer
2. Copy the 2.1.0 `.bin` and `.bin.sha` from the ctrtransfer `.zip` to the `/files9/` folder on your SD card
3. Reinsert your SD card into your 3DS
4. Press (B) to get to the Decrypt9 main menu
##### Section II - ctrtransfer
**Having a backup of _your_ device's NAND is REQUIRED. You will be prompted to create one as part of the steps if you do not already have one.**
{: .notice--danger}
**If you do not know whether or not you already have a NAND backup, create one when prompted by pressing (A) just to be sure.**
{: .notice--danger}
**If you do not have enough space to create the backup, you can either backup to a different SD card or clear space on your current SD card by pressing (Select) on the Decrypt9WIP main menu to eject your SD card and allow it to be swapped with a different SD card or to clear space on your current SD card**
{: .notice--danger}
1. Go to "SysNAND Options", then "CTRNAND Transfer", then "Auto CTRNAND Transfer"
2. Input the key combo given, then select the 2.1.0 ctrtransfer image when prompted by pressing (A)
3. If you do not already have a NAND backup, **backup SysNAND to `NANDmin.bin` when prompted by pressing (A)**
+ **Having a backup of _your_ device's NAND is REQUIRED.**
+ **Skipping this backup will result in the LOSS of all installed games and saves!**
4. Allow the transfer process to proceed automatically, this will take some time
5. Once the transfer is complete, press (B) to go back
6. Press (Select) to eject your SD card
7. Delete the 2.1.0 ctrtransfer image `.bin` and `.bin.sha` from the `/files9/` folder on your SD card
8. Press (Start) to reboot without reinserting your SD card
+ While on 2.1.0, the device will black screen on boot if your SD card is inserted before the home menu loads
+ Every time the device is rebooted on 2.1.0, you will need to take out your SD card before boot and put it back in after the home menu loads
+ For now, leave the SD card out as you will be copying files to it in the next page
+ This will be fixed once you restore your device in the next page
___
The initial boot of 2.1.0 can take slightly longer than a standard boot on some devices.
{: .notice--info}
*(Screen distortions or discolorations are normal for some devices while on 2.1.0, they will go away once you restore your backup)*
{: .notice--info}
{% capture notice %}
**Putting a New 3DS on 2.1.0 in sleep mode is known to cause an UNRECOVERABLE brick!**
**This only happens when shutting the lid _while the device is on_; this does not apply to turning the device off.**
**The device only enters sleep mode when the lid is closed. It is not on a timer or anything like that.**
**You should continue without delay to avoid any possibility of this happening!**
