Symbol ECP5U_45_CABGA381 and footprint LATTICE_BGA_CABGA381 already
cover this package generically; add the SamacSys-sourced STEP model
as a more accurate alternative body for manual per-instance
assignment, same treatment as the existing BG256 body.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SLWiTVT39zMvgWZfKNvYcP
