Which u-boot for rpi3? u-boot-rpi3-32 or the old one?

[bob prohaska]

Just noticed there are now two u-boot ports for the RPi3, one
called u-boot-rpi3-32 and (the presumably original) u-boot-rpi3.

The descriptions are equally bland, what's the difference?
The goal is to boot a recent snapshot of -current from USB
using a Pi3b (no +). Now it's suffering from cpu_reset failed.

Thanks for reading, apologies if it's a dumb question...

bob prohaska