Unable to boot into fastboot

Products Support DragonBoard 820c
#1

I just got my Dragonboard 820c and it boots fine with its initial boot, but it’s on an older kernel than I would like. So I follow this tutorial and created a boot.img with kernel 5.4, but now I am on the regular fastboot instructions and I am stuck. My board won’t go into fastboot mode, when I hold (-) and start up my board it will just restart and never do as its supposed to.

I then go into terminal and type cat /dev/zero > /dev/disk/by-partlabel/boot but I get “Permissions Denied”, I tried to sudo it but get the same result. I tried to chmod /dev but the same result. I tried to superuser but I do not know the password and it is not linaro.

Once I get passed this step, I am also unsure what to do with my boot.img

Any advice would be helpful.

#2

Try sudo su to switch to root before running the command.

which version of the Dragonboard 820c do you have, the one with UFS or eMMC?

#3

sudo su seemed to do the trick.

I have updated my board to kernel 5.4, but the os seems to be running at half-speed. Everything is lagging and takes 5-6 seconds per click to open windows and boxes. Any idea? Is this just the norm?

#4

The kernel source used for the snapshots doesn’t have the cpu frequency drivers, resulting in the CPU cores all running at fixed clocks, and unbelievably slow.

Take a peek here;

EDIT: I just checked my notes, and you would get the little cores running at 614 MHz, and the big cores running at a whopping 19 MHz.

#5

Exact, linaro qcomlt 5.4 branch is not currently in good shape for 820c. I will check internally what we can do, possibly merge your branch or cherry pick the missing patches.