Also tested on an OrangePi R2S (K1, 2 GiB, boots from eMMC), with the
same tree as the RV2 runs (upstream next plus these series and board
support that is not posted yet):
- the SPL starts the eMMC (SDH2, io clock moved from the BootROM's
409.6 MHz to 204.8 MHz through max-frequency) and loads U-Boot;
- U-Boot proper runs the eMMC in HS200 with tuning ("Mode: HS200
(200MHz)"), finds the EFI system partition and boots FreeBSD;
- FreeBSD then runs the eMMC at 200 MHz, 8-bit, without errors.
Patch 2 (SD only) and the failure path of patch 3 are not exercised on
this board.
