Clarify SD card instructions

Author: tehelsper

docs/advanced/flash-sd-card.md

@@ -2,6 +2,8 @@
 
 For many types of devices, including the Raspberry Pi 4, the first step in getting started is to download a MyNode image and flash it onto an SD card. The SD card is then inserted into the device so it can run the MyNode software.
 
+For some devices, like PCs and laptops, a USB thumbdrive can be used in place of the SD card using the same instructions.
+
 This same process can be done to load new versions of software, reset your password if it was forgotten, or to swap to a new SD card with larger storage capacity.
 
 ## What is an SD Card
@@ -32,7 +34,7 @@ You will need to download the image for your device from [mynodebtc.com/download
   </figure>
 </center>
 
-Once downloaded, the software software needs to be written to the SD card.
+Once downloaded, the software needs to be written to the SD card.
 
 ## Flash SD Card
 

docs/intro/getting-started.md

@@ -26,7 +26,7 @@ Follow the section the section that corresponds to your device.
 
 **Model Two**
 
-- Insert the micro SD card into the SD slot on the side of the device
+- Insert the provided micro SD card or USB flash drive into the device
 - Connect Ethernet cable to your device and your router or switch
 - Plug power cable in outlet and connect to device
 - Push power button to turn on device