Heltec V4's native USB-CDC peripheral doesn't implement the
SET_CONTROL_LINE_STATE request esptool's default DTR/RTS reset
depends on, so every write_flash attempt (and its fallback-baud
retry) failed identically with OSError: [Errno 71] Protocol error
on the TIOCMSET ioctl. Confirmed live on allshookup: firmware
downloaded fine but flashing failed every time, leaving the mesh
radio stuck unconfigured. Pass --before usb_reset for V4 (V3 keeps
default_reset, since its CP2102 UART bridge wires DTR/RTS through
correctly).
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
ssmithxandClaude Sonnet 5
cb5415ea5c