Sorry to necro an old thread, but I didn't find a more suitable one and I didn't want to start a new one.
Anyway, to the point.
When I install or build any of the Armbian dev/nightly images with kernel 5.x, the sdcard is practically unusable after the installation.
hdparm shows read/write speeds of max. 5 MB/sec. The reason is that unless the bus-width for mmc@4020000 is explicitly set to 4 bits in
sun50i-h6-orangepi-one-plus.dtb
mmc@4020000 {
compatible = "allwinner,sun50i-h6-mmc", "allwinner,sun50i-a64-mmc";
reg = <0x4020000 0x1000>;
clocks = <0x2 0x43 0x2 0x40>;
clock-names = "ahb", "mmc";
resets = <0x2 0x12>;
reset-names = "ahb";
interrupts = <0x0 0x23 0x4>;
status = "okay";
#address-cells = <0x1>;
#size-cells = <0x0>;
pinctrl-names = "default";
pinctrl-0 = <0xb>;
vmmc-supply = <0xc>;
bus-width = <0x4>;
cd-gpios = <0xd 0x5 0x6 0x1>;
phandle = <0x2f>;
};
the bus width defaults to 1 bit as seen in
root@orangepi:~# cat /sys/kernel/debug/mmc0/ios
clock: 50000000 Hz
actual clock: 50000000 Hz
vdd: 21 (3.3 ~ 3.4 V)
bus mode: 2 (push-pull)
chip select: 0 (don't care)
power mode: 2 (on)
bus width: 0 (1 bits)
timing spec: 2 (sd high-speed)
signal voltage: 0 (3.30 V)
driver type: 0 (driver type B)
which practically cripples the SD card interface. By default there is no bus-width entry in sun50i-h6-orangepi-one-plus.dtb for mmc@4020000. I don't know if this is Armbian specific or not or if this has been mentioned again, I just thought I'd share my findings in case this helps someone.