https://wiki.banana-pi.org/Banana_Pi_BPI-R3_Mini

• MT7986(Filogic 830) quad core ARM A53 SoC
• 2G DDR RAM
• 8G eMMC flash, SPI-NAND (128 MiB)
• 2x 2.5GbE network port (airoha en8811h phy)
• dual-band wifi:
  • 2.4G
  • 5G

connections from the edge of board: GND,RX,TX (remember RX/TX swap on your adapter :) )

my R3mini came preinstalled with vendors openwrt (21.02-SNAPSHOT, Linux version 5.4.171) on emmc and nand. i suggest to leave the nand to have always a rescue-system and only flash emmc as productive system with a more recent version.

It will take some time till i can release a full emmc-image for R3 Mini, but my uboot-repo generates already a very basic bpi-r3 emmc image (Releases Page) without rootfs/kernel which can be used on r3mini as well. Userspace can generated with the buildchroot.sh of my BPI-Images Repo or extracted from a full r3 Image.

Step-by-step:

used usb-stick to get files accessible from r3mini

started with r3-img:

gunzip -c /mnt/sda2/bpi-r3_bookworm_nokernel.img.gz |dd bs=1024 conv=notrunc,fsync of=/dev/mmcblk0

then flash uboot (wonder why there is no mmcblk0boot0 block to flash the bl2 - seems to be a problem with vendor-image, in my linux i see the boot0):

#r3mini/bl2_r3mini_emmc_pcie.img to boot0 conv=notrunc,fsync
dd if=/mnt/sda1/r3mini/fip_r3mini_emmc_pcie.bin bs=1024 conv=notrunc,fsync of=/dev/mmcblk0p4

Kernel (creates the bpi-r3.itb with conf-emmc-mini bootconfig):

https://github.com/frank-w/BPI-Router-Linux/tree/6.6-r3mini

need to drop the “run setbootconf;” from newboot first

BPI-R3M> run useusb
BPI-R3M> setenv initrd rootfs.cpio.zst
BPI-R3M> setenv fit r3mini/bpi-r3.itb
BPI-R3M> setenv bootconf "#conf-emmc-mini"
BPI-R3M> run newboot

how to get available bootconfigs from binary fit image:

dumpimage -l /media/frank/Android-x86/r3mini/bpi-r3.itb

DTS for reference:

https://github.com/BPI-SINOVOIP/BPI-R3MINI-OPENWRT-V21.02.3/blob/main/target/linux/mediatek/files-5.4/arch/arm64/boot/dts/mediatek/mt7986a-bananapi-bpi-r3mini-emmc.dts

BPI-R3M> fatload usb 0:1 $loadaddr r3mini/u-boot-pcie.bin                       
815592 bytes read in 73 ms (10.7 MiB/s)                                         
BPI-R3M> go $loadaddr                                                           
## Starting application at 0x46000000 ...                                       
                                                                                
                                                                                
U-Boot 2024.01-bpi-r3mini-00011-g5aadabca11e5-dirty

working in my r3mini uboot (2024-01-bpi-r3mini)

BPI-R3M> pci enum                                                               
drivers/pci/pcie_mediatek_gen3.c:mtk_pcie_startup_port[261] detected a card     
set trans table 0: 0x20000000 0x20000000, 0x10000000                            
BPI-R3M> pci                                                                    
BusDevFun  VendorId   DeviceId   Device Class       Sub-Class                   
_____________________________________________________________                   
00.00.00   0x14c3     0x1f32     Bridge device           0x04                   
01.00.00   0x1c5c     0x1327     Mass storage controller 0x08                   
BPI-R3M> nvme scan                                                              
BPI-R3M>                                                                        
BPI-R3M> nvme info                                                              
Device 0: Vendor: 0x1c5c Rev: 80002C00 Prod: ND94N163610404F0R                  
            Type: Hard Disk                                                     
            Capacity: 244198.3 MB = 238.4 GB (500118192 x 512)                  
BPI-R3M>

only working once then network is stalled

BPI-R3M> setenv ipaddr 192.168.90.2
BPI-R3M> ping 192.168.90.1         
Using ethernet@15100000 device
host 192.168.90.1 is alive
BPI-R3M> ping 192.168.90.1
Using ethernet@15100000 device

ARP Retry count exceeded; starting again
ping failed; host 192.168.90.1 is not alive
BPI-R3M>

This is fixed in my 2024-04 uboot by always run autonegotiation code (genphy code seems not working here).

In case nand and emmc are broken there is a way to load uboot via uart for reflash/fix bootchain of the storages.

https://forum.banana-pi.org/t/bpi-r3-mini-boot-from-nand-fails/17340/24

files here: https://drive.google.com/drive/folders/1b8KWe0p7fZmsRs9eBZUJBBISv3r2oUOR?usp=drive_link

$ ./mtk_uartboot -s /dev/ttyUSB5 --aarch64 --payload bpi-r3mini_ram_bl2.bin --fip bpi-r3mini_ram_fip.bin
mtk_uartboot - 0.1.1
Using serial port: /dev/ttyUSB5
Handshake...
hw code: 0x7986
hw sub code: 0x8a00
hw ver: 0xca01
sw ver: 0x1
Baud rate set to 460800
sending payload to 0x201000...
Checksum: 0x3663
Setting baudrate back to 115200
Jumping to 0x201000 in aarch64...
Waiting for BL2. Message below:
==================================
NOTICE:  BL2: v2.9(release):v2.9.0-357-g553a16af808e ram
NOTICE:  BL2: Built : 17:17:10, Mar  3 2024
NOTICE:  WDT: Cold boot
NOTICE:  WDT: disabled
NOTICE:  CPU: MT7986 (1998MHz)
NOTICE:  EMI: Using DDR4 settings
NOTICE:  EMI: Detected DRAM size: 2048MB
NOTICE:  EMI: complex R/W mem test passed
NOTICE:  Starting UART download handshake ...
==================================
BL2 UART DL version: 0x10
Baudrate set to: 921600
FIP sent.
==================================
NOTICE:  Received FIP 0x4d695 @ 0x40400000 ...
==================================

now you can use minicom or similar tool to get uboot-console and reflash bl2/fip to nand/emmc