What happened to the M.2. slot on the 4C+?

#1

The first 4C+ revision that I got was 1.2.
1.2 used to have a top M.2. key M slot.

Now the current revision is 1.41, which doesn’t have the slot anymore.
What was the reason behind removing the slot?
I had hoped to cut off a little PCB from the M.2. (B+M) version of the Google Coral Edge accelerator to fit on the board and use it on the 4C+…

I know that the change was made a long time ago, but I’m revisiting this topic for a project.
I’m aware that that’s a pretty specific use case but it would’ve been very convenient for me to still have the M.2. slot.

#2

I asked the same question, the informal answer was because one distributor requested it. Unfortunately even the PCB has changed, so the V 1.41 is more a 4C- is a backstep in my eyes.

#3

Damn, that’s sad. And I completely agree that it’s a backstep.
That M.2. slot is kind of a deal-breaker to me these days…

And the worst thing is that the 4C+ is I think currently the only RK3399 SBC that’s still getting software support. And yet it’s lacking a big feature… I could use a USB Coral (although I’d prefer not to because of space constraints), but I’m sure lots of people would like to have an SSD installed…

Especially since the 4 SE is ridiculous with its CPU on the bottom and outward-facing M.2. slot.
If I add the cooling and the M.2. extension to the 4 SE, the whole thing becomes way too big and bulky to use in my project.

#4

Honestly, all other Rock 4’s have the CPU on the bottom, so the 4C+ is the “exotic one”. The massive
passive cooler works very well for them and form the bottom plate of various shells, like the Rock NAS and the “official” shells, so it is not that bad. The 4C+ design tries to resemble a RPI 4B as much as possible. That works well to some extend, for instance you can use the ARGON.One shells. Still the SOC is not exactly at the place of the Broadcom, so the active cooler runs more often. That said, I was never able to run a 4B without active cooling for my task, which is one reason why I replaced it by Rocks. Hence, If you do not need the RPi 4B form factor or the two HDMI outputs, use a 4B(+) (more powerfull) or a 4SE (cheaper, reduced maximum frequency because of RK3399-T).

#5

Fair enough. And I know that my view is purely subjective and relates to a pretty specific use-case, but the thing is my projects aren’t stationary. I’m not exactly arguing with you here, rather putting the opinion out there for someone to maybe consider. The huge, bulky heatsink and the fact that the CPU is mounted on the bottom, completely rules out the 4 SE for me. But I know that for all other use cases it is fine (as long as it all it has to do is sit on the desk).