[CW340] Hello World Demo on CW340 returns SPI connection error, despite successful build and bitstream load.

Description

I am trying to run the hello world demo test following the FPGA build guide: https://opentitan.org/book/doc/getting_started/setup_fpga.html#flash-the-bitstream-onto-the-fpga-and-bootstrap-software-into-flash. I am able to load the bitstream with:

./bazelisk.sh run //sw/host/opentitantool -- fpga load-bitstream /tmp/bitstream-latest/chip_earlgrey_cw340/lowrisc_systems_chip_earlgrey_cw340_0.1.bit

which returns:

opentitan@bxqp8b3-ub22:~/Documents/opentitan$ ./bazelisk.sh run //sw/host/opentitantool -- fpga load-bitstream /tmp/bitstream-latest/chip_earlgrey_cw340/lowrisc_systems_chip_earlgrey_cw340_0.1.bit
INFO: Analyzed target //sw/host/opentitantool:opentitantool (0 packages loaded, 0 targets configured).
INFO: Found 1 target...
INFO: Elapsed time: 0.207s, Critical Path: 0.02s
INFO: 1 process: 1 internal.
INFO: Build completed successfully, 1 total action
INFO: Running command line: bazel-bin/sw/host/opentitantool/opentitantool
[00:00:20] [██████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████] 34.18 MiB/34.18 MiB (0s)

Then the build command runs successfully:

opentitan@bxqp8b3-ub22:~/Documents/opentitan$ bazel build //sw/device/examples/hello_world
DEBUG: /home/opentitan/Documents/opentitan/rules/autogen.bzl:452:14: NOTE: stamping is disabled, the chip_info section will use a fixed version string
INFO: Analyzed target //sw/device/examples/hello_world:hello_world (0 packages loaded, 1414 targets configured).
INFO: Found 1 target...
Target //sw/device/examples/hello_world:hello_world up-to-date:
bazel-bin/sw/device/examples/hello_world/hello_world_fpga_cw310.bin
bazel-bin/sw/device/examples/hello_world/hello_world_fpga_cw310.elf
bazel-bin/sw/device/examples/hello_world/hello_world_fpga_cw310.dis
bazel-bin/sw/device/examples/hello_world/hello_world_fpga_cw310.map
bazel-bin/sw/device/examples/hello_world/hello_world_fpga_cw340.bin
bazel-bin/sw/device/examples/hello_world/hello_world_fpga_cw340.elf
bazel-bin/sw/device/examples/hello_world/hello_world_fpga_cw340.dis
bazel-bin/sw/device/examples/hello_world/hello_world_fpga_cw340.map
bazel-bin/sw/device/examples/hello_world/hello_world_sim_dv.64.scr.vmem
bazel-bin/sw/device/examples/hello_world/hello_world_sim_dv.elf
bazel-bin/sw/device/examples/hello_world/hello_world_sim_dv.dis
bazel-bin/sw/device/examples/hello_world/hello_world_sim_dv.map
bazel-bin/sw/device/examples/hello_world/hello_world_sim_dv.logs.txt
bazel-bin/sw/device/examples/hello_world/hello_world_sim_dv.rodata.txt
bazel-bin/sw/device/examples/hello_world/hello_world_sim_dv.64.vmem
bazel-bin/sw/device/examples/hello_world/hello_world_sim_verilator.64.vmem
bazel-bin/sw/device/examples/hello_world/hello_world_sim_verilator.elf
bazel-bin/sw/device/examples/hello_world/hello_world_sim_verilator.dis
bazel-bin/sw/device/examples/hello_world/hello_world_sim_verilator.map
INFO: Elapsed time: 0.576s, Critical Path: 0.06s
INFO: 1 process: 1040 action cache hit, 1 internal.
INFO: Build completed successfully, 1 total action

Then when attempting hello world demo:

opentitan@bxqp8b3-ub22:~/Documents/opentitan$ bazel run //sw/host/opentitantool -- bootstrap "$(ci/scripts/target-location.sh //sw/device/examples/hello_world | grep fpga_${BOARD}.bin)"
INFO: Analyzed target //sw/host/opentitantool:opentitantool (0 packages loaded, 1281 targets configured).
INFO: Found 1 target...
INFO: Elapsed time: 0.406s, Critical Path: 0.04s
INFO: 1 process: 986 action cache hit, 1 internal.
INFO: Build completed successfully, 1 total action
INFO: Running command line: bazel-bin/sw/host/opentitantool/opentitantool
Error: SFDP header contains incorrect signature: 0xffffffff

This is after applying the change in location-target.sh:
From: REL_PATH=$(${REPO_TOP}/bazelisk.sh outquery "$@" 2>$REDIR)
To: REL_PATH=$(${REPO_TOP}/bazelisk.sh cquery --output=files "$@" 2>$REDIR)

Any advice or help to resolve the SPI issue and get the hello world test up and running?

Start with the FPGA setup guide, the sw/host/opentitantool bootstrap entry point, and ci/scripts/target-location.sh. Reproduce the CW340 bootstrap command and investigate the SFDP header contains incorrect signature: 0xffffffff result. Done means the bootstrap completes without the SPI error and the hello world demo runs on the CW340.