[porschemad911]

Summary

u-boot: S922X: mainline u-boot v2026.07

Testing

Tested ok on my OGU, tested ok on @ddrsoul's OGU: https://discord.com/channels/948029830325235753/1035228339952160878/1557020565393510411

Additional Context

Migrate from BSP u-boot to mainline

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AI Usage

Did you use AI tools to help write this code? NO

[ShigeakiAsai]

SD card reads fail after a reboot from Linux (OGU, U-Boot 2026.07)

I'm moving Lakka's ODROID-GO Ultra build to mainline U-Boot 2026.07 as well, and hit this on the OGU.

Symptom

After a reboot from Linux, U-Boot reads extlinux.conf, then fails on the kernel with Error reading cluster. Every read after that fails (No partition table - mmc 0), and it drops to the U-Boot prompt. A cold boot is fine.

Cause

Linux sets vddio_c (RK818 LDO9, the vqmmc supply of the SD card) to 3.0V:

vddio_c                   3000mV   (1800-3300mV)
   ffe05000.mmc-vqmmc     3000mV  3300mV

It is still at 3.0V when U-Boot starts after a reboot. At the U-Boot prompt:

=> pmic dev pmic@1c
=> pmic read 0x54
0x54: 0x6c                 <- LDO9 = 3.0V
=> mmc read 0x1000000 0 1
MMC read: dev # 0, block # 0, count 1 ... 0 blocks read: ERROR
=> pmic write 0x54 0x6f    <- 3.3V
=> mmc rescan
=> mmc read 0x1000000 0 1
MMC read: dev # 0, block # 0, count 1 ... 1 blocks read: OK

Whether reads fail at 3.0V probably depends on the card; mine is a SanDisk 64GB. I haven't seen this with the vendor U-Boot or with 2025.07.

Also, U-Boot's rk8xx regulator driver only describes RK818 LDO1-8, so the regulator command can't read or set vddio_c (it shows 0 uV / disabled).

Fix

Two small patches on top of 2026.07:

1. power: regulator: rk8xx: add RK818 LDO9 support
   LDO9's enable bit is bit 5 of DCDC_EN (sleep: SLEEP_SET_OFF1), and its voltage is in BOOST_LDO9_ON/SLP_VSEL (1.8-3.4V, 100mV steps).
2. arm: dts: meson-g12b-odroid-go-ultra-u-boot: set vddio_c to 3.3V
regulator-init-microvolt = <3300000>, like the existing vcc_2v3 and vdd_ee entries.

With both, 9 reboots in a row (from RetroArch and reboot) all booted.

Lakka commits:

• ShigeakiAsai/Lakka-LibreELEC@170916a1dc (U-Boot 2026.07 for S922X)
• ShigeakiAsai/Lakka-LibreELEC@472b20ca03 (the two patches above)

Feel free to use them. I worked through this with Claude's help.

Thanks,
Asai, Shigeaki

[porschemad911]

Replaced by #3474