VLD down

I have an issue with my tangNano board.
With gowin programmer (gui) or programmer_cli for all command (read user code, flash SRAM, flash embFlash, …) the tool stop with the message:
Error: VLD Down!

I have no idea of the reason why this message is displayed, the only one reference to VLD is TN653 (JTAG) and no options in programmer seems to allows to revert for a correct state.

Someone could help me to fix this?


Sorry to insist…
Thanks to openFPGALoader I’m able to load bitstream in FPGA’s SRAM (thing not possible with official tool)

But openFPGALoader has problem with the ch552 to write the flash (see this issue).

After some try and with a second tangNano (with the ch552 bypassed according to this tweet)) I can confirm this tool is working with GW1N-1 but only if VLD bit is set.

Must I consider my board has must be considered as dead.
Nobody to providing help?