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.
**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.**
**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!**
**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 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)*:
+ <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)
**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**