Update newbs docs with some rp2040 stuff (#21186)

* Update newbs_building_firmware_configurator.md

* Update docs/newbs_flashing.md


Co-authored-by: Ryan <fauxpark@gmail.com>

docs/newbs_building_firmware_configurator.md

@@ -4,6 +4,8 @@
 
 The [QMK Configurator](https://config.qmk.fm) is an online graphical user interface that generates QMK Firmware `.hex` or `.bin` files.
 
+It should be noted that Configurator cannot produce firmwares for keyboards using a different controller than they were designed for, i.e. an RP2040 controller on a board designed for pro micro. You will have to use the command line [converters](https://docs.qmk.fm/#/feature_converters?id=supported-converters) for this.
+
 Watch the [Video Tutorial](https://www.youtube.com/watch?v=-imgglzDMdY). Many people find that is enough information to start programming their own keyboard.
 
 The QMK Configurator works best with Chrome or Firefox.

docs/newbs_flashing.md

@@ -15,7 +15,7 @@ Different keyboards have different ways to enter this special mode. If your PCB
 * Press the physical `RESET` button, usually located on the underside of the PCB
 * Locate header pins on the PCB labeled `RESET` and `GND`, and short them together while plugging your PCB in
 
-If you've attempted all of the above to no avail, and the main chip on the board says `STM32` on it, this may be a bit more complicated. Generally your best bet is to ask on [Discord](https://discord.gg/Uq7gcHh) for assistance. It's likely some photos of the board will be asked for -- if you can get them ready beforehand it'll help move things along!
+If you've attempted all of the above to no avail, and the main chip on the board says `STM32` or `RP2-B1` on it, this may be a bit more complicated. Generally your best bet is to ask on [Discord](https://discord.gg/Uq7gcHh) for assistance. It's likely some photos of the board will be asked for -- if you can get them ready beforehand it'll help move things along!
 
 Otherwise, you should see a message in yellow, similar to this in QMK Toolbox:
 
@@ -31,6 +31,8 @@ The simplest way to flash your keyboard will be with the [QMK Toolbox](https://g
 
 However, the Toolbox is currently only available for Windows and macOS. If you're using Linux (or just wish to flash the firmware from the command line), skip to the [Flash your Keyboard from the Command Line](#flash-your-keyboard-from-the-command-line) section.
 
+?> QMK Toolbox is not necessary for flashing [RP2040 devices](https://docs.qmk.fm/#/flashing?id=raspberry-pi-rp2040-uf2).
+
 ### Load the File into QMK Toolbox
 
 Begin by opening the QMK Toolbox application. You'll want to locate the firmware file in Finder or Explorer. Your keyboard firmware may be in one of two formats- `.hex` or `.bin`. QMK tries to copy the appropriate one for your keyboard into the root `qmk_firmware` directory.