17c5d8d110
The Firefly-RK3399 board does not boot reliably in the SJG lab due to signal-integrity issues with SD-wire adapters at higher speeds. Reduce the SDMMC max-frequency to 25MHz and disable high-speed modes to improve compatibility. Co-developed-by: Claude Opus 4.5 <noreply@anthropic.com> Signed-off-by: Simon Glass <simon.glass@canonical.com>