BPI-R3 Mini won't boot from EMMC

Banana Pi Router design BPI-R3/R3 Mini(MT7986)
1

BPI-R3 Mini does not respond to boot switch NAND/EMMC ! Booting always happens from NAND, no matter where I move the switch.

root@OpenWrt:~# ls /dev
bus           log           mmcblk0       mtd0          ptmx          ttyS10        ttyS6         ubi0_3
cdc-wdm0      loop-control  mmcblk0boot0  mtd0ro        pts           ttyS11        ttyS7         ubi0_4
console       loop0         mmcblk0boot1  mtd1          random        ttyS12        ttyS8         ubi0_5
fd            loop1         mmcblk0p1     mtd1ro        shm           ttyS13        ttyS9         ubi_ctrl
fit0          loop2         mmcblk0p128   mtdblock0     stderr        ttyS14        ttyUSB0       ubiblock0_4
full          loop3         mmcblk0p2     mtdblock1     stdin         ttyS15        ttyUSB1       urandom
gpiochip0     loop4         mmcblk0p3     nul           stdout        ttyS2         ubi0          watchdog
hwrng         loop5         mmcblk0p4     null          tty           ttyS3         ubi0_0        watchdog0
i2c-0         loop6         mmcblk0p5     port          ttyS0         ttyS4         ubi0_1        zero
kmsg          loop7         mmcblk0rpmb   ppp           ttyS1         ttyS5         ubi0_2

EMMC visible on boot.

EC: 0000 0000 [1000]

always 1000 Is this a hardware problem?

2

Is the switched snapped on emmc position? Maybe you see some mechanical problem on the switch (soldering points, broken lane,electrical bridge,…)?

3

position NAND - boot from nand, position EMMC - boot from nand I checked the switch with a multimeter, it’s fine. I didn’t look at the track, but the soldering seems normal.

4

Emmc is always visible as the switch only changes the bootstrap (which device should be booted from bootrom)…if the EC value always same it seems to be hardware issue…this is from bootrom which displays the bootstrap value

Screenshot_20240427-185521
Screenshot_20240427-185521985×1069 235 KB

5

Sadly. Thank you ! I’ll try to check the diagram.

6

Thanks a lot for the tip! I soldered SW1 properly and everything worked!