[doc] Better explain HyperDebug flashing

At least two people have been understandably confused by error message `Error: Firmware programming failed: Unable to establish connection after flashing. Possibly bad image.` when using opentitantool to flash HyperDebug firmware for the first time. The cause being that with the jumper wire left in place, the board will not boot into the firmware just flashed, but instead boot into the DFU bootloaded again. Adding an explicit step in the instructions calling for removing the jumper wire _before_ running opentitantool should hopefully avoid this. Change-Id: I2cdd333c12ebe566252482a1ba9eacf288a5eaec Signed-off-by: Jes B. Klinke <[email protected]>
lowRISC · Feb 12, 2025 · 057b716 · 057b716
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Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/doc/getting_started/setup_fpga.md b/doc/getting_started/setup_fpga.md
@@ -223,7 +223,8 @@ Below we describe how to:
 1. Move jumper JP6 to select `5V_USB_C`.
 1. Move jumper JP4 to select `3.3V` mode (_this will be changed before connecting to CW340_).
 1. Use a USB-C cable to connect your PC with the `USB1` power and data connector near the blue and black push buttons.
-1. Using a jumper wire, connect pins 5 and 7 on bank CN11, and hit the black `RESET` push button to put the device in DFU mode (the red and blue LEDs whould be solid to indicate you have entered DFU mode).
+1. Using a jumper wire, connect pins 5 and 7 on bank CN11, and hit the black `RESET` push button to put the device in DFU mode.
+1. Remove the jumper wire, the red and blue LEDs should remain on indicating the board is in DFU mode.
 1. Flash the firmware by running `cd $REPO_TOP && ./bazelisk.sh run //sw/host/opentitantool -- --interface=hyperdebug_dfu transport update-firmware`.
 
 Note: after flashing the HyperDebug firmware for the first time, it can be updated (*without* needing to put the board into DFU mode) by running the same command used above to flash the firmware for the first time.