Enabling 8 GB RAM on Banana Pi BPI‑R4

Work in Progress – testing ongoing
Director: AKADATA LIMITED

Source thread: https://forum.banana-pi.org/t/bpi-r4-frank-w-bpi-r4-u-boot-build-flash-nand/23112
Frank Wunderlich’s repositories supply the base code and build scripts referenced below.

Status

• Verification currently under way on two production boards.
• Once both units pass cold‑boot and 24‑hour memory‑stress, pre‑built images, checksums, and a one‑line installer will be published here.
• Feedback from additional testers is welcomed in the forum thread above.

Prerequisites

1  Clone sources

# All paths are relative to $HOME/bpir4-wip
mkdir -p $HOME/bpir4-wip && cd $_
# Frank's current branches
git clone https://github.com/frank-w/u-boot -b 2025-04-bpi u-boot-r4   # U‑Boot
git clone https://github.com/frank-w/u-boot -b mtk-atf-2025 mtk-atf-2025   # ATF/BL2

Inline comments clarify each command.
Lines beginning with # are safe to copy; bash ignores them.

2  Prepare configuration files

2.1 build.conf for both trees

cat > build.conf <<'EOF'
board=bpi-r4
device=spi-nand
extraflags=DDR4_4BG_MODE=1   # enables 8 GB training
EOF

The same three‑line file lives in the root of each repository.

2.2 Add 8 GB size to ATF’s DRAM list

vim mtk-atf-2025/plat/mediatek/mt7988/drivers/dram/dram-configs.mk

Inside dram-configs.mk locate:

AVAIL_DRAM_SIZE := 1024 2048

…and extend it to:

AVAIL_DRAM_SIZE := 1024 2048 4096   # 4096 MB × 2 ranks = 8 GB

Removing DRAM_USE_COMB=1 (if present) avoids detection stalls.

3  Build artefacts

3.1 U‑Boot

cd u-boot-r4
./build.sh importconfig       # loads board defaults
./build.sh build              # ~3 min on Ryzen 5
./build.sh rename             # creates u-boot-r4_2025.04-arm64-spi-nand.bin

3.2 ATF / BL2

cd ../mtk-atf-2025
./build.sh build              # outputs bl2.img and fip.bin

4  Flash BL2 & FIP to SPI‑NAND

Important: This step changes the boot ROM hand‑off; keep a serial cable attached.

# At the U‑Boot prompt; USB stick on port 0 holds the new binaries
usb start                                # initialise storage
mtd erase spi-nand0                      # full wipe
load usb 0:5 ${loadaddr} bl2.img         # BL2 at offset 0x0
mtd write spi-nand0 ${loadaddr} 0x0 0x100000
load usb 0:5 ${loadaddr} fip.bin         # FIP at offset 0x580000
mtd write spi-nand0 ${loadaddr} 0x580000 0x200000
reset

Inline offsets follow Frank’s original layout; adjust when booting from eMMC.

5  Confirm 8 GB detection

During the early BL2 log the UART should display:

NOTICE:  EMI: DDR4 4BG mode
NOTICE:  EMI: Detected DRAM size: 8192 MB

Linux, once started, reports approximately 7.7 GiB:

free -h
              total        used        free      shared  buff/cache   available
Mem:          7.7Gi       76Mi       7.4Gi       16Mi      132Mi       7.4Gi
Swap:            0B         0B         0B

Absence of the 8192 MB line indicates the size flag or DRAM list is still missing.

6  Rollback procedure

setenv skip_bl2 1   # ignore BL2 on next boot
saveenv
reset

The board falls back to the previous loader stored in on‑chip ROM.
Use this only for recovery; remove skip_bl2 once the fix is applied.

7  Next steps

• Automation: A single install-8g.sh is being drafted to wrap steps 2‑5.
• Binary releases: Pre‑built bl2.img and fip.bin will be hosted in the same forum thread with SHA‑256 sums.
• Documentation merge: After double‑confirmation, this article’s commands will enter the mainline BPI‑R4 wiki.

Community collaboration is appreciated. Questions and test reports belong in the forum link cited above.

Changelog

End of document — work in progress.