Banana Pi M2 Ultra (R40): fails to boot with CURRENT kernel, OK on LEGACY

[igorpecovnik]

Split out from the sunxi u-boot v2026.07 migration (#10069).

Summary

Banana Pi M2 Ultra (Allwinner R40, BOARDFAMILY=sun8i, KERNEL_TARGET=current,edge,legacy) boots fine on the LEGACY kernel but fails to boot on the CURRENT kernel.

This is a kernel-branch issue, not u-boot — it was found while validating the sunxi u-boot bump to v2026.07-rc4 (#10069), and the u-boot port itself is confirmed working (the board boots on legacy with the new u-boot). So it should be tracked/fixed independently of the u-boot migration.

Status

• u-boot v2026.07-rc4 (sunxi bump, sunxi (32-bit): bump u-boot v2024.01 -> v2026.07-rc4 [DRAFT migration] #10069): ✅ builds + boots (legacy kernel)
• current kernel: ❌ does not boot
• legacy kernel: ✅ boots fine

Needed to diagnose

• Serial console log of the current-kernel boot up to where it stops (does it reach Starting kernel? hang point / panic?).
• Confirm whether edge behaves like current or like legacy.

Notes

R40 (sun8iw11) current/edge kernel support is the likely area — DT, clocks, or a driver regression vs the legacy branch. Not a regression from the u-boot work.

cc: ref #10069

[colinvail6]

I have been having this same issue on my BPi M2U. I am currently using legacy kernel version 6.18.35-current-sunxi, the newest one did not boot.

[colinvail6]

I also noticed that there was no boot delay (no kernel loading)