I’m trying to design a clean boot setup for my Banana Pi R4 (8GB) with these goals:
- Normal boot of OpenWrt rootfs from NVMe (ideally eMMC → NVMe, or NAND → NVMe)
- Ability to insert an SD card with a snapshot build and boot it easily for testing
- Easy rootfs upgrades later (e.g.
sysupgrade?)
From what I understand, the easiest path may be to install Fran’s U-Boot since it supports PCIe on R4 and uEnv.txt.
I’d like to confirm a few points:
- Is NVMe boot on R4 currently supported in upstream U-Boot / OpenWrt snapshot U-Boot, or is Fran’s build still required?
- If I install Fran’s U-Boot, can I follow @ycfunet’s tutorial as-is, or are there important changes due to newer U-Boot/OpenWrt versions?
- When tutorials mention “switch to eMMC boot and boot into U-Boot menu”, does this imply I must use a USB–TTL serial adapter to interact with U-Boot? (I have a CH340-based adapter /1a86:7523/, and I’ve read about some problems connected to its led)
- Is the recommended layout still:
- Bootloader on eMMC (or NAND)
- Kernel + rootfs on NVMe
- SD card overrides boot when present?
I followed those two threads:
- [BPI-R4] Failed attempt: add NVMe support on uboot - #76 by frank-w
- [BPI-R4] frank-w BPI-R4 u-boot Build & Flash (NAND) - #10 by pswel1
but any pointers to up-to-date documentation or best practices would be greatly appreciated.
Thanks!