SiFive Unmatched: Linux kernel doesn't start (U-Boot 2024.07)

[Yuri Zaporozhets]

Hi all,

To all owners & active users of the SiFive Unmatched board: do you have success
running any recent upstream U-Boot on your system?

I use the default U-Boot from Ubuntu 24.04, and it boots GRUB and Linux
kernel just fine. Today I flashed the unmodified U-Boot 2024.07 (compiled with
"make sifive_unmatched_defconfig" and OpenSBI 1.5), and the Ubuntu kernel
(6.8) doesn't boot at all. The last message I see on the console is:

EFI stub: Exiting boot services...

Adding "earlycon=sbi debug" doesn't change anything.

The same behavior is also when GRUB is excluded from the process:

=> nvme scan
=> load nvme 0:5 $kernel_addr_r /boot/vmlinuz
38603264 bytes read in 47 ms (783.3 MiB/s)
=> bootefi $kernel_addr_r
Booting /\boot\vmlinuz
EFI stub: Booting Linux Kernel...
EFI stub: EFI_RNG_PROTOCOL unavailable
EFI stub: Using DTB from configuration table
EFI stub: Exiting boot services...

Is some additional patch needed to run U-Boot on Unmatched?

-- 
Regards,
Yuri