Merge pull request #391 from LitBomb/patch-13

Update faq.md

Author: ripplebiz

docs/faq.md

@@ -64,9 +64,11 @@ author: https://github.com/LitBomb<!-- omit from toc -->
   - [6.3. Q: How to connect to a repeater via BLE (Bluetooth)?](#63-q-how-to-connect-to-a-repeater-via-ble-bluetooth)
   - [6.4. Q: I can't connect via Bluetooth, what is the Bluetooth pairing code?](#64-q-i-cant-connect-via-bluetooth-what-is-the-bluetooth-pairing-code)
   - [6.5. Q: My Heltec V3 keeps disconnecting from my smartphone.  It can't hold a solid Bluetooth connection.](#65-q-my-heltec-v3-keeps-disconnecting-from-my-smartphone--it-cant-hold-a-solid-bluetooth-connection)
+  - [6.6. Q: My RAK/T1000-E/xiao\_nRF52 device seems to be corrupted, how do I wipe it clean to start fresh?](#66-q-my-rakt1000-exiao_nrf52-device-seems-to-be-corrupted-how-do-i-wipe-it-clean-to-start-fresh)
 - [7. Other Questions:](#7-other-questions)
   - [7.2 Q: How to update ESP32-based devices over the air?](#72-q-how-to-update-esp32-based-devices-over-the-air)
   - [7.1 Q: How to update nRF (RAK, T114, Seed XIAO) repeater and room server firmware over the air using the new simpler DFU app?](#71-q-how-to-update-nrf-rak-t114-seed-xiao-repeater-and-room-server-firmware-over-the-air-using-the-new-simpler-dfu-app)
+  - [7.2 Q: Is there a way to lower the chance of a failed OTA device firmware update (DFU)?](#72-q-is-there-a-way-to-lower-the-chance-of-a-failed-ota-device-firmware-update-dfu)
 
 ## 1. Introduction
 
@@ -533,6 +535,27 @@ You can get the epoch time on <https://www.epochconverter.com/> and use it to se
 
 **A:** Heltec V3 has a very small coil antenna on its PCB for Wi-Fi and Bluetooth connectivity.  It has a very short range, only a few feet.  It is possible to remove the coil antenna  and replace it with a 31mm wire.  The BT range is much improved with the modification.
 
+### 6.6. Q: My RAK/T1000-E/xiao_nRF52 device seems to be corrupted, how do I wipe it clean to start fresh?
+
+**A:** 
+1. Connect USB-C cable to your device, per your device's instruction, get it to flash mode:
+    - For RAK, double click its reset button
+    - For T1000-e, quickly disconnect and reconnect the magnetic side of the cable from the device TWICE
+    - For Heltec T114, click the reset button once (the bottom button)
+    - For Xiao nRF52, click the reset button once.  If that doesn't work, quickly double click the reset button twice.  If that doesn't work, disconnection the board from your PC and reconnect again ([seeed studio wiki](https://wiki.seeedstudio.com/XIAO_BLE/#access-the-swd-pins-for-debugging-and-reflashing-bootloader))
+5. A new folder will appear on your computer's desktop
+6. Download the `flash_erase*.uf2` file for your device on flasher.meshcore.co.uk 
+    - RAK WisBlock and Heltec T114: `Flash_erase-nRF32_softdevice_v6.uf2`
+    - Seeed Studio Xiao nRF52 WIO: `Flash_erase-nRF52_softdevice_v7.uf2`
+8. drag and drop the uf2 file for your device to the root of the new folder
+9. Wait for the copy to complete.  You might get an error dialog, you can ignore it
+10. Go to https://flasher.meshcore.co.uk/, click `Console` and select the serial port for your connected device 
+11. In the console, press enter.  Your flash should now be erased
+12. You may now flash the latest MeshCore firmware onto your device
+
+Separately, starting in firmware version 1.7.0, there is a CLI Rescue mode.  If your device has a user button (e.g. some RAK, T114), you can activate the rescue mode by hold down the user button of the device within 8 seconds of boot.  Then you can use the 'Console' on flasher.meshcore.co.uk 
+
+
 ---
 ## 7. Other Questions:
 
@@ -558,12 +581,25 @@ You can get the epoch time on <https://www.epochconverter.com/> and use it to se
 4. Go to the Command Line tab, type `start ota` and hit enter.
 5. you should see `OK` to confirm the repeater device is now in OTA mode
 6. Run the DFU app,tab `Settings` on the top right corner
-7. Enable `Packets receipt notifications` and change `Number of Packets` to 10 for RAK, 8 for T114.  8 also works for RAK.  
-8. Select the firmware zip file you downloaded
-9. Select the device you want to update. If the device you want to updat is not on the list, try enabling`OTA` on the device again
-10. Tab the `Upload` to begin OTA update
-11. If it fails, try turning off and on Bluetooth on your phone.  If that doesn't work, try rebooting your phone.  
-12. Wait for the update to complete.  It can take a few minutes.
+7. Enable `Packets receipt notifications`, and change `Number of Packets` to 10 for RAK, 8 for T114.  8 also works for RAK.  
+9. Select the firmware zip file you downloaded
+10. Select the device you want to update. If the device you want to updat is not on the list, try enabling`OTA` on the device again
+11. If the device is not found, enable `Force Scanning` in the DFU app
+12. Tab the `Upload` to begin OTA update
+13. If it fails, try turning off and on Bluetooth on your phone.  If that doesn't work, try rebooting your phone.  
+14. Wait for the update to complete.  It can take a few minutes.
+
+### 7.2 Q: Is there a way to lower the chance of a failed OTA device firmware update (DFU)?
+
+**A:** Yes, developer `che aporeps` has an enhanced OTA DFU bootloader for nRF52 based devices.  With this bootloader, if it detects that the application firmware is invalid, it falls back to OTA DFU mode so you can attempt to flash again to recover.  This bootloader has other changes to make the OTA DFU process more fault tolerant. 
+
+Refer to https://github.com/oltaco/Adafruit_nRF52_Bootloader_OTAFIX for the latest information.
+
+Currently, the following boards are supported:
+- Nologo ProMicro
+- Seeed Studio XIAO nRF52840 BLE
+- Seeed Studio XIAO nRF52840 BLE SENSE
+- RAK 4631
 
 
 ---