Hello. I just received my Sweet Potato and I’m trying to get it running. I’m attempting to boot from a USB hard drive, more specifically a HDTB520XK3AA. The image I flashed was this Debian image. I decompressed the archive and flashed the .img using Balena Etcher to the USB hard drive. However, no dice when booting. Looking at the log, the only thing that stands out is “scanning usb for storage devices… 0 Storage Device(s) found”. I read the specifications for the USB hard drive I’m using and it claims to be able to run off USB 2.0 power alone with no external power needed. The Sweet Potato boots off a USB flash drive just fine so I disregarded the posts on the forum saying you need to use a blank SD card or eMMC to boot from USB. I tried all 4 USB ports on the Sweet Potato and the error log stays the same. I do not believe it’s an issue with power delivery as the indicator light on the USB hard drive is the same as when it’s plugged into a normal computer but isn’t mounted.
If it’s a spinning hard drive, those things suck a tremendous amount of current on startup. It also takes them time to be read. Interrupt u-boot and then type in usb reset followed by usb info to see if it shows up.
Hello, thanks for the reply. I used the commands you gave and it only detects the keyboard and the USB hubs. The USB hard drive is not detected as a connected device and isn’t detected as a storage device either. I looked at the specifications for the USB hard drive and it says that it draws a maximum of 900mA, however it also specifies that it works fine under USB 2.0 which has a maximum of 500mA if I’m not mistaken. I tried it on USB 2.0 ports on a different machine and it worked fine. If there is a power limitation what would you recommend for high capacity storage?
Charles: it may say it also works with USB 2, but given the 900mA current spec that’s at best only sorta true. No USB 2 compliant port is guaranteed to provide 900mA, even if a majority of those in desktop and laptop machines - surely the design target of the Canvio series - will do so in practice.
I’ve been using a number of SSDs in USB-SATA enclosures without power problems, but these are smaller, older SSDs from back in the days of TLC - 32G, for example. I was going to say that the power budgets were much lower then, but they actually weren’t lower in terms of watts per TB. 
So the Canvio or something like it is probably the best you can do, leaving the problem of feeding it enough juice to get it spinning at start up. I did have one SSD that was marginal for power (1), and connecting it by way of an external hub with its own (optional) power supply made it work reliably. What would probably be ideal would be an external enclosure that was designed with a separate power input, though those may be rare these days.
(1) I think this was testing with the same hub (unpowered) on La Frite, which hasn’t so many USB sockets on board?
Yeah, I’m just assuming it’s a power delivery issue. When plugging in the USB hard drive after the Sweet Potato is already booted it causes a drop in power that reboots the Sweet Potato. I had an external hard drive bay for full sized HDDs that has an external power connector so I’m just using that for the time being.