key-info: os compatibility, sd backup

- Some exploits currently require Windows or Linux, so key-info has been updated accordingly
- Add SD backup non-collapsible warning

_pages/en_US/key-information.txt

@@ -32,7 +32,9 @@ This guide works with every retail console in the Nintendo 3DS family of console
 <summary><strong>Computer compatibility</strong></summary>
 ![]({{ "/images/screenshots/onboarding/os.jpg" | absolute_url }})
 {: .notice--info}
-You can follow this guide as long as you are able to download files from the Internet and copy them to your SD card. Depending on your computer/phone/electronic device, you may need to purchase a USB to SD card adapter to allow your computer to read your SD card.
+In most cases, you can follow this guide as long as you are able to download files from the Internet and copy them to your SD card. Depending on your computer/phone/electronic device, you may need to purchase a USB to SD card adapter to allow your computer to read your SD card.
+
+Some methods (notably, Kartminer7 and MSET9) may require a traditional computer running Windows or Linux. If you are unable to get access to a computer using those operating systems, you will need to follow another method.
 {% endcapture %}
 
 <details>{{ compat | markdownify }}</details>
@@ -68,6 +70,9 @@ In short: Modding your console is safe, but it's ___your responsibility___ if so
 
 ## Things you need to do on your computer
 
+Following this guide alone should not result in data loss, but SD card corruption is always a possibility. You should make a backup of your SD card contents (especially the `Nintendo 3DS` folder) if you have important data.
+{: .notice--warning}
+
 {% capture compat %}
 <summary><strong>File placement terminology (e.g. "root of SD")</strong></summary>
 ![]({{ "/images/screenshots/onboarding/sdroot.png" | absolute_url }})