fix: Revert to manual reset for OpenOCD 0.12.0 compatibility

- The 'srst_assert_width' flag is not supported in 0.12.0.
- Revert to using manual 'ftdi_set_signal' commands to pulse the
  nSRST line, which is the correct method for older OpenOCD versions.
- This should fix both the syntax error and the 'mpsse_flush' timeouts.

openocd-reboot.cfg

@@ -1,4 +1,5 @@
-# OpenOCD Configuration to REBOOT a SiFive HiFive Pro P550 Board (v3)
+# OpenOCD Configuration to REBOOT a SiFive HiFive Pro P550 Board (v4)
+# Compatible with OpenOCD 0.12.0
 
 # ----------------------------------------------------------------
 # 1. Adapter and Board Configuration
@@ -6,10 +7,6 @@
 adapter driver ftdi
 ftdi channel 2
 ftdi vid_pid 0x0403 0x6011
-
-# NEW: Set the JTAG clock speed.
-# Start with a conservative but reasonable speed. 1000 kHz = 1 MHz.
-# If this works, you can try increasing it to 5000 or 10000 for faster performance.
 adapter speed 1000
 
 ftdi layout_init 0x0808 0x0a1b
@@ -33,23 +30,31 @@ target smp riscv.cpu0 riscv.cpu1 riscv.cpu2 riscv.cpu3
 # 3. Reset Configuration and Execution
 # ----------------------------------------------------------------
 
-# MODIFIED: Changed the reset configuration.
-# By removing 'srst_pulls_trst', we are telling OpenOCD to handle the
-# JTAG reset (nTRST) and the system reset (nSRST) as separate signals.
-# This is often more reliable on complex SoCs.
-reset_config srst_only srst_assert_width 100 srst_deassert_delay 100
+# Configure the reset type, but without the unsupported timing flags.
+# We will control the pulse manually.
+reset_config srst_only
 
 # Initialize OpenOCD and connect to the target
 init
 
-# --- The Improved Reboot Sequence ---
-# 'reset halt' asserts the reset line, then immediately halts the cores
-# as they come out of reset, before they can execute any code.
-echo "!!! Issuing reset halt to gain control..."
-reset halt
+# --- Manual Reboot Sequence for OpenOCD 0.12.0 ---
+echo "!!! Manually asserting system reset (nSRST)..."
+# Pull nSRST low (active low, so '0' asserts it)
+ftdi_set_signal nSRST 0
+# Hold the reset for 100ms to ensure the board registers it
+sleep 100
 
-# Now that the system is halted and stable, we can let it run.
-echo "!!! Resuming execution to complete the reboot..."
+echo "!!! De-asserting system reset and attempting to halt..."
+# Release nSRST (set it back to high-impedance/inactive)
+ftdi_set_signal nSRST 1
+# Wait a moment for the board to start coming out of reset
+sleep 100
+
+# Immediately after releasing reset, halt the cores.
+# This is the critical step to catch them before they boot the OS.
+halt
+
+echo "!!! System halted successfully. Resuming execution to boot..."
 resume
 
 # Exit OpenOCD