Comment 42 for bug 1848703

About the problem of "there is no /dev/mmcblk0* device", I checked your dmesg, there are two places are weird

the 1st one is about the raspberrypi-firmware, on my board, the dmesg will show:
[ 0.100540] raspberrypi-firmware soc:firmware: Attached to firmware from 2019-08-15 12:03, variant start
[ 0.110122] raspberrypi-firmware soc:firmware: Firmware hash is 9f8431fb7839c7f00f52b81f5822ddab2b31d0db

And there are not errors about firmware, but your dmesg is different.

the 2nd one is about mmc-bcm2835 driver, your kernel always report: mmc-bcm2835 fe300000.mmcnr: could not get clk, deferring probe

That is different from my board, on my board, it only reports that message once, Then the driver could get the clk successfully.