Hello,
hope this information is useful for somebody who own this particular TV box.
This recovery procedure applly to the H20 box with PCB H20-221-V1.71-2-B
Symptoms: Red LED burn, nothing happen on the screen. Complete dead.
Install or compile rkdeveloptool
sudo apt-get install libudev-dev libusb-1.0-0-dev dh-autoreconf
git clone https://github.com/rockchip-linux/rkdeveloptool
cd rkdeveloptool
autoreconf -i
./configure
make
Short the board and connect to the PC with a male to male USB cable.
Check that you are in maskrom mode
$ sudo rkdeveloptool ld
DevNo=1 Vid=0x2207,Pid=0x320b,LocationID=501 Maskrom
Download the Bootloader MiniLoaderAll_1.11.253.bin
$ sudo rkdeveloptool db MiniLoaderAll_1.11.253.bin
Downloading bootloader succeeded.
Check now for available flash module
$ sudo rkdeveloptool rfi
Flash Info:
Manufacturer: SAMSUNG, value=00
Flash Size: 7456 MB
Flash Size: 15269888 Sectors
Block Size: 512 KB
Page Size: 2 KB
ECC Bits: 0
Access Time: 40
Flash CS: Flash<0>
Now write the dump to the flash
Download the h20-backup.dump https://mega.nz/file/SZ433bJA#RQZTSJrsjyJWOXlFWV6TLaqxMB0-C4JtExWyQbAyqp8
$ sudo rkdeveloptool wl 0 h20-backup.dump
Write LBA from file (100%)
Disconnect usb cable.
The Tv Box should now start with a blue LED.