I encountered the black screen problem or the problem that the machine became bricked as many folks here did.
I also tried all the ROM versions
1.63, 1.82, 1.87, 1.9, but in vain.
After careful study of the config.txt file in the BurnTool, I finally came to the conclusion that my main board was NOT SUPPORTED simply because the board carries the NAND flash marked "H27UAG8T2M" which is not listed in the config.txt file. I also found another main board that carries a different NAND chip "K9GAG08U0M" which in included in the config.txt, indicating that it is supported. The latter machine never becomes bricked.
SO the key issue for the bricked machine becomes very simple and very tough: How can we or anyone upgrade the BurnTool so that it supports the Hynix chip?
I tried to add the chip to the "Nand Supported Count" list, the added line reads like:
nand75 = 0xADD514B644, 4096, 128, 2048, 4096, 2048, 128, 2, 15, 3, 11, 0x2, 0x10000001, 0xf5ad1, 0x50303, Hynix H27UAG8T2M
Unluckily, it failed again.
Anyone has a better solution?