If you have already hacked your device before and have a EmuNAND based CFW setup, this guide deals exclusively with SysNAND and you should follow all instructions from within or applying to SysNAND. Note that the terms EmuNAND and RedNAND refer to slightly different implementations of [the same concept](http://3dbrew.org/wiki/NAND_Redirection).
If you downgrade to 2.1.0 on a 2DS or New 3DS and leave 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 2.1.1. Ensure you have a microSD card reader available before proceeding.
**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. If you cannot disable parental controls because the linked NNID is for a child under 13, you can instead set all parental control options to "do not restrict".**
**Performing a CtrTransfer will remove all user-installed tickets (which allow access to games) from your device until the created backup is restored.**
**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!**
In this section, we will be flashing your device'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 device. 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 device specific files (such as `moveable.sed` and `SecureInfo_A`) to it, then fixing the title databases.
+ <i class="fa fa-magnet" aria-hidden="true" title="This is a magnet link. Use a torrent client to download the file."></i> - [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)
+ <i class="fa fa-magnet" aria-hidden="true" title="This is a magnet link. Use a torrent client to download the file."></i> - [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)
+ <i class="fa fa-magnet" aria-hidden="true" title="This is a magnet link. Use a torrent client to download the file."></i> - [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)
1. Remove your SD card from your device, leaving it on the Homebrew Launcher, then insert your SD card into your computer
1. Create a folder named `CtrTransfer` on the root of your SD card if it does not already exist
1. Copy the 2.1.0 `.bin` and `.bin.sha` from the CtrTransfer `.zip` to the `/CtrTransfer/` folder on your SD card
1. Copy `safehax.3dsx` to the `/3ds/` folder on your SD card
1. Copy `fasthax.3dsx` to the `/3ds/` folder on your SD card
1. Copy `SafeCtrTransfer.bin` from the SafeCtrTransfer `.zip` to the root of your SD card and rename `SafeCtrTransfer.bin` to `safehaxpayload.bin`
1. Reinsert your SD card into your device
##### Section II - Launch SafeCtrTransfer
1. Launch fasthax from the list of homebrew
+ You may have to scroll down to see this option
1. Once it has completed, press (Start) to exitfasthax
+ This may take several tries
+ If it freezes, just force the console to power off by holding the power button, then try again
1. Launch safehax from the list of homebrew
+ You may have to scroll down to see this option
+ If it freezes, just force the console to power off by holding the power button, then try again
1. If the exploit was successful, you will have booted into SafeCtrTransfer
##### Section III - CtrTransfer
1. Allow the SafeCtrTransfer initialization and safety checks to proceed automatically
+ If you get an error, ensure you have all files in the correct locations and that you have enough free space on your SD card as detailed in [Get Started](get-started)
1. When prompted, input the key combo given to confirm CtrTransfer to 2.1.0
+ This process will take some time
+ This process will automatically create a backup of your device's NAND at `/ctrtransfer/<serialnumber>_nand.bin`
+ If you get an error, [follow this troubleshooting guide](troubleshooting#transfer)
1. Press (A) to reboot once it has completed
+ While on 2.1.0, your device will black screen on boot if your SD card is inserted before the home menu loads
+ Every time your 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