On Fri, Oct 31, 2025 at 12:10:36PM +0800, Sune Brian wrote: > Hello U-Boot maintainers, > > While testing mainline U-Boot (v2026.01-rc1-00070-ge34d01d23e45) on the > FriendlyARM NanoPi NEO4 (RK3399), I observed that SPL sometimes fails to > initialize the SD card with the following message: > > spl: mmc init failed with error: -5 > SPL: failed to boot from all boot devices > > After investigation, the root cause appears to be related to the **SD card > power rail (`vcc3v0_sd`) timing during SPL startup**. On the NanoPi NEO4, > the SD slot is powered via GPIO0_A1 to a fixed 3.0 V supply. SPL may attempt > MMC initialization **before this supply has fully stabilized**, resulting in > a generic I/O error (`-5`). The SD card itself and the controller are > functioning correctly once the supply is stable. > > **Workarounds / fixes observed:** > - Add a small delay after enabling `vcc3v0_sd` before SPL starts MMC init. > - Ensure the regulator is fully powered and stable at SPL start. > > This appears to be a **hardware/platform-specific power-on timing issue** > rather than a device tree or software bug, but documenting it would help > users encountering similar errors on the NanoPi NEO4. > > **Hardware:** FriendlyARM NanoPi NEO4 > **SoC:** Rockchip RK3399 > **U-Boot version:** v2026.01-rc1-00070-ge34d01d23e45 > **Reproducibility:** 100% with SD boot
Adding the board maintainer and come other active rockchip people. -- Tom
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