Unable to Boot Alpine Linux ISO with UEFI on U-Boot

I am having trouble booting Alpine Linux 3.20.2 AArch64 ISO (alpine-standard-3.20.2-aarch64.iso) using U-Boot in UEFI mode (UEFI + Devicetree) on the NanoPi R5S board. This issue seems specific to the Alpine Linux image, as I have successfully booted a Fedora image. Original issue: inindev/uboot-rockchip#2

Environment:

• Board: NanoPi R5S
• Bootloader: U-Boot 2024.07
• OS Version: Alpine Linux 3.20.2

The boot process failed with the following error:

Mounting boot media failed.
initramfs emergency recovery shell launched.

It appears that the OS is unable to detect any storage devices:

(initramfs) cat /proc/partitions
major minor  #blocks name
    1     0     4096 ram0
    1     1     4096 ram1
...
    1    15     4096 ram15

I would appreciate any guidance on how to address this issue.