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).
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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.
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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. 请注意该功能在2.1.0系统上不可用。请确保在开始本教程之前,你手头已有一个SD卡读卡器。
{: .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.**
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**Disable the parental controls of your device before doing the 2.1.0 CTRTransfer. 如果你不知道密码,参见[这里](https://mkey.salthax.org/)。 如果你的 NNID 因为是给低于13岁的小孩所设置的而无法关闭家长监护的话,你可以将各个家长监护选项停用。 **
{: .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.**
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. 此OTP文件在安装arm9loaderhax的过程中必不可少,并且**不能**在不同设备间共享。
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.
#### 你需要:
* DS flashcart that works on your device version
* The latest release of [SafeCTRTransfer](https://github.com/d0k3/SafeCTRTransfer/releases/latest)
* The 2.1.0 CTRTransfer image for your device and region
*(如果你的设备不在下列地区中,请随便选一个)*:
+ <i class="fa fa-magnet" aria-hidden="true" title="下载链接。 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="下载链接。 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="下载链接。 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)
#### 操作指南
##### Section I - Prep Work
1. Power off your device
1. 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 `SafeCTRTransfer.dat` from the SafeCTRTransfer `.zip` to the root of your SD card
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