Rock64 4Gb variant bricked

[magare]

When pin 20 clamped to GND, "SPI-FLASH-ROM" can not be read.
Therefore, boot-loader skips "SPI-FLASH-ROM", and boot from SD-Card.

However, in the clamped state, virtually "SPI-FLASH-ROM" is disable (it can not be read), so probably can not erase it.
I think that it is necessary to release the clamp promptly, after boot starts from the SD-Card.

What is the procedure you performe

Thanks for your help.
1. Power off the board
2. insert the SD card with either u-boot-erase-spi-rock64.img.xz or u-boot-flash-spi-rock64.img.xz loaded onto the card.
3. short pin 20 and 21
4. Power on the board
5. Remove the bridge from the pins in 5 seconds. I tried longer and shorter time and it was all the same.
6. White LED starts flashing with one second intervals. Keeps flashing for ever.
7. Power off the board.
8. insert an SD card with latest Armbian image on it.
9. Power on the board
10. All LED are on and nothing happened.
Hope the situation is a bit clearer.
Thanks for helping out !!!
Cheers.