Since Tumbleweed 20210317, when booting up a Raspberry Pi 3, only one of the
four CPUs comes online. I tested this on a clean install from the ISO and on a
Zypper dup from 20210223.

dmesg output:
[    0.005122] smp: Bringing up secondary CPUs ...
[    5.041231] CPU1: failed to come online
[    5.041253] CPU1: failed in unknown state : 0x0
[   10.083487] CPU2: failed to come online
[   10.083513] CPU2: failed in unknown state : 0x0
[   15.126053] CPU3: failed to come online
[   15.126078] CPU3: failed in unknown state : 0x0
[   15.126172] smp: Brought up 1 node, 1 CPU
[   15.126186] SMP: Total of 1 processors activated.

I will run further tests with an older kernel and report back.