Guide_3DS/_pages/zh_CN/include/exploit-usm.txt

In this section, you will enter Safe Mode (a feature available on all 3DS family devices) and navigate to a menu where unSAFE_MODE will be triggered, which will launch you into the boot9strap (custom firmware) installer.

1. 将你的主机置于关机状态，按住 L + R + ↑ + A 四个按键，然后按下电源键
  + 按住这几个键，直到主机进入安全模式（一个“系统更新”菜单）
{%- if include.method == "hbl" or include.method == "kartdlphax" %}
  + If you're unable to get into Safe Mode after multiple attempts, one of your buttons may be failing or broken. If this is the case, join [Nintendo Homebrew on Discord](https://discord.gg/MWxPgEp) and ask, in English, for help.
{%- elsif include.method == "bb3" %}
  + If you're unable to get into Safe Mode after multiple attempts, one of your buttons may be failing or broken. If this is the case, you will need to follow [an alternate branch of BannerBomb3](installing-boot9strap-(fredtool)). 如需帮助，请加入 [Nintendo Homebrew on Discord](https://discord.gg/MWxPgEp) 并使用英文求助。（请注意，如果你身处中国大陆，访问 Discord 可能需要科学上网），你也可以到译者的 [QQ 群](https://stray-soul.site/index.php/qqgroup)寻求帮助，群号为 942052497。
{%- endif %}
1. Press "OK" to accept the update
  + There is no update. This is part of the exploit
1. Press "I accept" to accept the terms and conditions
1. The update will eventually fail, with the error code `003-1099`. This is intended behaviour
1. When asked "Would you like to configure Internet settings?", select "Yes"
1. On the following menu, navigate to `Connection 1` -> `Change Settings` -> `Next Page (right arrow)` -> `Proxy Settings` -> `Detailed Setup` ([image](/images/screenshots/usm/safemode_highlighted.png))
1. If the exploit was successful, your device will have booted into SafeB9SInstaller