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. EmuNANDとRedNANDは[同じ理論](http://3dbrew.org/wiki/NAND_Redirection)の少々違う実装です。
{: .notice--info}
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.
{: .notice--info}
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. 事前にmicroSDカードリーダーをご用意ください。
{: .notice--info}
To use the [magnet](https://en.wikipedia.org/wiki/Magnet_URI_scheme) links on this page, you will need a torrent client like [Deluge](http://dev.deluge-torrent.org/wiki/Download)
{: .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. パスワードがわからない場合は、[このサイト](https://mkey.salthax.org/)をご覧ください。 十三歳以下の子供のためのNNIDをリンクしているため、「保護者による使用制限機能」を無効にできない場合、全ての使用制限を「制限なし」に設定してください。**
{: .notice--warning}
**Performing a CTRTransfer will remove all user-installed tickets (which allow access to games) from your device until the created backup is restored.**
{: .notice--danger}
**バージョン6.0.0以下で2DSでは本体が壊れる為絶対に初期化しないで下さい。**
{: .notice--danger}
**New 3DSで2.1.0へのダウングレード後は本体設定から更新を実行すると3DSが壊れるのでご注意下さい。 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. このOTPファイルはarm9loaderhaxをインストールするために必要です。他の本体では**利用できません**。
<br><br>
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="トレント用のマグネットリンク。 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="トレント用のマグネットリンク。 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="トレント用のマグネットリンク。 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)
#### 手順
##### セクション I - 準備
1. Power off your device
1. パソコンにSDカードを入れます
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 `SafeCTRTransfer.dat` from the SafeCTRTransfer `.zip` to the root of your SD card
1. `starter.zip` の_中身_をSDカード直下にコピーします
1. Reinsert your SD card into your device
1. Copy `SafeCTRTransfer.nds` from the SafeCTRTransfer `.zip` to your DS flashcart
1. Power on your device
##### Section II - Launch SafeCTRTransfer
1. Start your DS flashcart from your device
1. Boot `SafeCTRTransfer.nds` using your flashcart
1. Select the correct option for your system version
+ 4.X.X -> "4.x SafeCTRTransfer"
+ 6.X.X -> "6.x SafeCTRTransfer"
1. Reboot the system, then go to System Settings, then "Other Settings", then "Profile", then "Nintendo DS Profile"
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 a critical error, [follow this troubleshooting guide](troubleshooting#ts_transfer)
1. Once this process has completed, remove your SD card from your device to reboot
+ The reboot will take about 2 seconds to trigger
+ 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
+ For now, leave your SD card out as you will be copying files to it in the next page
