Helios64: Update troubleshoot page

docs/helios64/troubleshoot.md

@@ -15,19 +15,15 @@ If problem still occurs, please capture the serial console output and report it
 
 ### Kernel Panic
 
-If [System Error LED](/helios64/front-panel/#helios64-enclosure) blinking, there was kernel panic.
+If [System Error LED](/helios64/front-panel/#helios64-enclosure) blinking, there was kernel panic. Please reset the system.
 
 If problem still occurs, please capture the serial console output and report it to forum.
 
 ### Network down
 
-#### Solution 1
-
 Verify whether Ethernet LED turned on. If it is not, try to unplug and re-plug the network cable.
 
-#### Solution 2
+If network still down, try other Ethernet port.
-
-Try other Ethernet port.
 
 ### Corrupted filesystem
 
@@ -36,19 +32,53 @@ Boot from micro SD card and execute following command to repair system partition
 ```
 fsck -p /dev/mmcblk1p1
 ```
-
 or
-
 ```
 btrfs check --repair /dev/mmcblk1p1
 ```
-
 if your system partition formatted with BTRFS.
 
 ### Micro SD card slot broken
 
 Try to flash OS directly to eMMC using [maskrom mode](/helios64/maskrom/)
 
+### Old bootloader
+
+On October 5th, 2020 there was device tree (dtb) filename change. It applied to Armbian 20.08.8.
+Originally the filename is **rk3399-helios64.dtb** and changed into **rk3399-kobol-helios64.dtb**
+
+Boot from micro SD card and execute following commands
+
+```
+sudo mkdir -p /mnt/system
+sudo mount /dev/mmcblk1p1 /mnt/system
+sudo ln -sf rk3399-kobol-helios64.dtb /mnt/system/boot/dtb/rockchip/rk3399-helios64.dtb
+sudo umount /mnt/system
+sudo poweroff
+```
+
+Remove the micro SD card and power on the system.
+
+After boot successfully to eMMC, we strongly suggest to update the bootloader using armbian-config.
+
+### Rootfs is not accessible
+
+If you have transfer the rootfs to SATA or USB, make sure the device is still accessible and you don't remove the device.
+
+Boot from micro SD card and execute following command,
+
+```
+sudo mkdir -p /mnt/system
+sudo mount /dev/mmcblk1p1 /mnt/system
+grep "rootdev" /mnt/system/boot/armbianEnv.txt
+```
+Take note of UUID value and run,
+
+```
+sudo blkid
+```
+Verify if you have device with the same UUID. If the device is accessible, it might have corrupted filesystem. Run *fsck* to check and fix it.
+
 ---
 
 ## Problem: Serial console does not appear
@@ -61,3 +91,35 @@ Make sure you have FTDI VCP driver installed. You can download the driver from [
 
 Make sure jumper P13 is open otherwise it will disable the built-in USB to Serial converter. Refer to [USB Console/Recovery Mode (P13)](/helios64/jumper/#usb-consolerecovery-mode-p13)
 
+### Cable is not plugged correctly
+
+When you put the back panel make sure to align the port and push a bit before securing with screw.
+
+![! backpanel connector](/helios64/img/troubleshoot/backplate_connector.jpg)
+
+If the USB-C port cannot hold the cable properly and loose the cable, you need to shave the cable a bit so the plastic does not touch the back panel.
+
+![! usb cable](/helios64/img/troubleshoot/usb_cable_shaved.jpg)
+
+Photo from [TDCroPower at Armbian Forum](https://forum.armbian.com/topic/15431-helios64-support/page/4/?tab=comments#comment-110859)
+
+---
+
+## Problem: I have broken bootloader on eMMC and unable to boot, how to force boot from micro SD ?
+
+Make sure the system is powered off and insert the micro SD card.
+Short [P10](/helios64/jumper/#boot-mode-p10-p11) with jumper cap, power on and remove the jumper cap before boot Linux (~5 seconds after power on).
+
+## Problem: How to clean up the eMMC
+
+### System still booting from eMMC after deleting the partition
+
+Bootloader located between first block and first partition. Clearing partition table does not remove the bootloader.
+
+Execute following command to erase Partition table, bootloader and partition superblock.
+
+```
+sudo dd if=/dev/zero of=/dev/mmcblk1 bs=512 count=65535
+sudo sync
+```
+