sigilOS boots to the login on a real Pi 3B — blue framebuffer probe + all 5 green stage squares (fb-init, sb_valid, font, scene, composite) → the login card rendered on real hardware.
Root cause: board_pi3's pi3_mbox_fb_init mailbox failed on real Pi 3B where the test card's gfx_setup() succeeded — the diff was the property-tag message format, not the mailbox call itself. Fix: verbatim mailbox format matching the proven test card.
gfx_setup verbatim
Real Pi 3B framebuffer init — uses the exact mailbox property-tag message format that the test card proved works on real hardware. Blue FB probe confirms framebuffer is live, 5 green stage squares confirm each boot stage completes.