Add Silicon Labs EFR32/EZSP flashing info and links (#1574)

* Add Silicon Labs EFR32/EZSP flashing info and links

Add Silicon Labs EFR32/EZSP flashing info and links

* Update README.md silabs-flasher

Update README.md silabs-flasher

* Link to puddly's Universal Silicon Labs Flasher

Added URL to puddly's Universal Silicon Labs Flasher

docs/guide/adapters/README.md

@@ -565,8 +565,20 @@ Adapters based on CC1352 or CC2652 chips can be flashed by putting them in the b
 #### Flashing an existing adapter
 The above flashing tools can be used to upgrade the firmware on an existing adapter without needing to repair devices. See the [FAQ](https://www.zigbee2mqtt.io/guide/faq/#what-does-and-does-not-require-repairing-of-all-devices) for information on what does and does not require repairing of devices.
 
+### Flashing Silabs EFR32/EM358x/ETRX35x based adapters
+
+Firmware updates to Zigbee EmberZNet (EZSP) adapter based on EFR32, EM358x, and ETRX35x chips from Silicon Labs can be flashed over USB/UART by putting them in bootloader (BSL) mode. If your adapters has an EM358x or ETRX35x chip it will have an older/legacy Ember Bootloader (EBL) and you will need to see your adapter manual on how to put your adapter into bootloader mode, also known as boot mode or firmware recovery mode. After you have done this one of the following tools/guides can be used to flash it. If your adapter has a EFR32xG1 or EFR32MG2x chip adapters then it will have the newer Gecko Bootloader (GBL) that has the ability to enter bootloader mode automatically (also known as Auto-BSL) without need to pressing holding physical BTL/reset button or short circuit any GPIO/soldering-pads.
+
+- [Elelabs Firmware Update Utility](https://github.com/Elelabs/elelabs-zigbee-ezsp-utility/) (multi platform Python based command line tool)
+- [puddly Universal Silicon Labs Flasher](https://github.com/puddly/universal-silabs-flasher) (multi platform Python based command line tool)
+- [agners silabs-flasher - Silicon Labs Firmware flashing utility](https://github.com/agners/silabs-flasher) (multi platform Python based command line tool)
+- [walthowd husbzb-firmware script](https://github.com/walthowd/husbzb-firmware) (community maintained multi platform bash script)
+- [Manual Xmodem sending commands over a terminal console](https://sonoff.tech/wp-content/uploads/2022/08/SONOFF-Zigbee-3.0-USB-dongle-plus-firmware-flashing-.pdf) (note that any terminal application with "Xmodem(N)" send can be used)
+- Silicon Labs [Simplicity Studio](https://www.silabs.com/developers/simplicity-studio) included "Flash Programmer" ([instructions](https://docs.silabs.com/simplicity-studio-5-users-guide/latest/ss-5-users-guide-building-and-flashing/flashing#flash-programmer)) (can't find your device? read below!)
+- [Additional programming options for Silicon Labs MCU based devices](https://www.silabs.com/developers/mcu-programming-options)
+
 #### Is your OS unable to find your device?
-If you're asking yourself "Why won't my dongle or adapter show up?" when you are using (for example) Flash Programmer 2, chances are that your OS can't communicate with your device over VCP (Virtual COM Port), causing your dongle not showing up as a flashable device. To fix this problem, be sure to install a USB-to-UART bridge VCP driver like the one at [Silicon Labs](https://www.silabs.com/developers/usb-to-uart-bridge-vcp-drivers) or [FTDI Chip](https://ftdichip.com/drivers/vcp-drivers/).
+If you're asking yourself "Why won't my dongle or adapter show up?" when you are using (for example) Flash Programmer 2, chances are that your OS can't communicate with your device over VCP (Virtual COM Port) serial port, causing your dongle not showing up as a flashable device. To fix this problem, be sure to install a USB-to-UART bridge/converter VCP driver for your operating system like the one at [Silicon Labs](https://www.silabs.com/developers/usb-to-uart-bridge-vcp-drivers), [FTDI Chip](https://ftdichip.com/drivers/vcp-drivers/), or [WCH (CH34x/CH91xx)](http://www.wch-ic.com/downloads/category/30.html).
 
 ### Router
 Besides serving as a coordinator some adapters can also be used as a Zigbee router (check if there is a router firmware by clicking on your adapter). To factory reset/pair: