Hi Forum - apologies, but I’m feeling a little bit lost. Should the eMMC module on my Pi board pop-off? Should I be able to prise it off? I’m a bit scared, it looks to be surface mounted like the other chips on the board.
So, I found a video on youtube and went ahead and built the kit, and I have a USB stick with the downloaded and etcher’d OS on it, but when I power on the box, all four drives spin up but I get no output on HDMI at all.
Clearly there is no OS on the eMMC, and also the Rock Pi 4B+ also appears to be unable to boot from USB.
What can/should I do next?
Thank you.
Dave.
ROCK Pi 4B+, and Penta SATA HAT kit from AllNet
haha - think I’ve worked out what to try… take the case off, take the hard drives off, unseat the hat, insert a micro SD card (already etcher’d with image plus a copy of the image again) in the Rock Pi, re-seat the hat, then boot - and now I see that it books ok - and then dd the same IMG on to the /dev/mmcblk0
now sad again 
after dd’ing the image to the eMMC, it wouldn’t fully boot, so popped it all apart again and put SD card back in, and still now it won’t fully boot… symptoms: green power lights on hat and rock pi - but I get two flashes from blue LED on the rock pi, a gap, then same two flashes, and it never ends.
now I really am stuck, no idea what to try next.
found some pretty poor instructions online, and realised that I’d overwritten the boot SD card (mmcblk0) - eventually found another later Ubuntu focal server (stable?) image, re-imaged my boot SD, rebooted, and this time dd’d over the eMMC module mmcblk1 - and then removed SD card, booted into eMMC proper - yay! - and then gingerly picked my way through the rest of the build steps - trying to figure what not to do - and then found some more instructions in French - anyway - it’s now built to the point of the Penta hat is up, and working, OLED, and fans, and all four HDD are seen.
Anyone got any tips on what I can install and configure to get a RAID-5 array built and some kind of SMB shares or NFS exports setup?
well… I got there in the end… found some instructions for mdadm based RAID, got that created, and then a samba share created.
any news on whether Ubuntu server 22.04 LTS might ever be supported for Rock Pi4B plus Penta hat?
any chance you could share those instructions? I’m at the same point, it boots from SD but I’m unsure how to flash the soldered emmc.