Quote from Ddren on September 21, 2019, 8:35 am

It is possible to repair 187B or 187A noname after loading a corrupted hmi file (also possible for other files). If your unit restarts every 60 seconds, this method can help you.

What you need:

• USB -> TTL/UART converter,

• some thin wires or socket,

• SD card,

• Very good soldering skills or a friend with such skills.

Part 1. Connection with unit

Disassemble the unit. At the top of the motherboard there are pads for sockets. Find the socket on the right.

Make sure that the layout of other components such as resistors is the same as in the photos

The 6 and 7 leads to the socket are RX and TX for our converter. Solder the wires or socket and connect with the converter (rx to tx and tx to rx), you can take the ground from the power supply.

On your computer run your favorite serial terminal (I use putty), select the COM port of your converter and set the baud rate to 115200.

Part 2. Prepare SD card

Make sure your SD card is in mbr format.

Format it in FAT32.

Extract the contents of the update package to your SD card.

Insert the sd card into the unit

Part 3. Prepare unit

Start the unit. If you have done everything correctly, you will see the process of booting the unit on the computer screen.

Press and hold enter as soon as you start.

if you can see the line:

(none) login:

quickly type:

 root

press enter, paste this command:

mount -o remount rw / && mkdir /sd 

and press enter.

PS. Don't worry about what's displayed on the screen.

Part 4. Interrupt watchdog

Important: You have to do it really fast.

Press and hold the enter until you see it:

(none) login:

quickly type:

 root

press enter, paste this command:

mount -o remount rw / && mount -t vfat /dev/mmcblk0 /sd -o rw,umask=0000 && cd /sd/opt && ./launch.sh > /dev/null

and press enter.

If you are fast enough, you will see a lot of errors on the screen. After a while the errors will stop displaying but the unit will not restart.

if you're sure that everything worked out, you can move on.

Part 5. Restore orginal files

if you have a corrupted hmi file, paste this command:

cp /sd/opt/hmi /opt/hmi && chmod 777 /opt/hmi

and press enter.

if you have a corrupted other file then adjust the command to your needs.

after all corrupt files have been restored, execute the command:

reboot

download1 187A noname original hmi file for sw 5314

download2 187B noname original hmi file for sw5406