Rock64 4Gb variant bricked

[magare]

OK.
Currently, I will proceed with the premise that you are logged in and able to operate.

To clarify the story, The "OS-Image" to be used is
limited to "stretch-minimal-rock64-0.7.9-1067-arm64.img.xz", that is presented earlier.

---
The following explains flash erasing and writing concretely
After logging in, unclamp Pin 21 and Pin 20.
All operations are done with root privilege.

The time required for work is,
"Erase" about 15 seconds, and "Write" about 10 seconds.


"Erase"

Code:

# ls /dev/mtd*
ls: cannot access '/dev/mtd*': No such file or directory

# enable_dtoverlay mtd spi@ff190000 disabled
 ....(message out)

# enable_dtoverlay mtd spi@ff190000 okay
 ....(message out)

# ls /dev/mt*
/dev/mtd0  /dev/mtd0ro  /dev/mtdblock0

# flash_erase /dev/mtd0 0 0

"Writing"

Code:

# dd of=/dev/mtd0 if=./xxx.img bs=4K

*If xxx.img is necessary, pick it directly from u-boot-rockchip-rock64-xxx.deb of the following url and use it.
https://github.com/ayufan-rock64/linux-u-boot/releases
 Example)
 "u-boot-rockchip-rock64-2017.09-rockchip-ayufan-1033-gdf02018479.deb"

"Erase & Writing"

Code:

# mkdir u-boot; cd u-boot;
# wget https://github.com/ayufan-rock64/linux-u-boot/releases/download/2017.09-rockchip-ayufan-1033-gdf02018479/u-boot-rockchip-rock64-2017.09-rockchip-ayufan-1033-gdf02018479.deb

# dpkg -x u-boot-rockchip-rock64-2017.09-rockchip-ayufan-1033-gdf02018479.deb ./tmp
# find ./tmp -name "*.img"
./tmp/usr/lib/u-boot-rock64/rksd_loader.img

# flash_erase /dev/mtd0 0 0
# dd of=/dev/mtd0 if=./tmp/usr/lib/u-boot-rock64/rksd_loader.img bs=4K

good luck.

---

Sorry, it was a mistake again.
x "stretch-minimal-rock64-0.7.9-1067-arm64.img.xz" -> o "bionic-minimal-rock64-0.7.9-1067-arm64.img.xz"

Perfect !!! 

After enabling the device tree overlay and re-flashing the SPI area everything works fine again !!!

Thank you so much for your time and effort !!!

Cheers