The pinned rpi-rgb-led-matrix commit emits the ARMv7-only `dmb ishst`
instruction in lib/rp1/rp1_rio_backend.cc, guarded only by __arm__, so the
build fails on every ARMv6 board ("selected processor does not support
`dmb ishst' in ARM mode"). Bump the pin to upstream 1ee4f76, which merges
12d839f (guard on __ARM_ARCH >= 7) plus docs only.
The installer also needed two changes for that bump to reach anyone:
- git pull never moves an existing submodule checkout, so a device that
already failed would keep building the broken commit. The build step now
moves the checkout forward to the pin — never backward or sideways (a
`git submodule update --remote` checkout is left alone), and never fatal.
- The submodule git commands ran as root on the user's clone (git's SUDO_UID
exemption allows it), leaving .git/modules/rpi-rgb-led-matrix-master
root-owned and the user unable to run git in it. They now run as the
project directory's owner, and root-owned leftovers are handed back.
Root-owned installs keep running as root.
test/test_install_rgb_checkout.py covers the non-root sync scenarios under
the installer's strict mode, checks that every called _helper is defined
before use, and pins the one-shot-install.sh -> first_time_install.sh
contract. Verified the tests fail on five deliberate mutations. Root/owner
scenarios were exercised manually under WSL Ubuntu, and the library was
cross-compiled for arm1176jzf-s at both pins (old: rp1_rio_backend.cc fails
at line 120; new: 16/16 sources compile).
Co-authored-by: Claude Opus 5 <noreply@anthropic.com>
