Re: Boot from USB on RPi4 8GB?

From: William Carson via freebsd-arm <freebsd-arm_at_freebsd.org>
Date: Thu, 10 Jun 2021 19:22:00 -0500
> On May 30, 2021, at 6:54 PM, William Carson via freebsd-arm <freebsd-arm_at_freebsd.org> wrote:
> 
>> 
>> On May 30, 2021, at 4:08 PM, Mark Millard <marklmi_at_yahoo.com> wrote:
>> 
>> On 2021-May-30, at 13:50, Mark Millard via freebsd-arm <freebsd-arm at freebsd.org> wrote:
>> 
>>> On 2021-May-30, at 10:59, William Carson via freebsd-arm <freebsd-arm at freebsd.org> wrote:
>>> 
>>>>> . . .
>>>>> I use a USB3 SSD that has small enough power requirements
>>>>> to not require a powered hub. (I also use a 5.1V 3.5A
>>>>> power supply as part of that context.) I've never tried
>>>>> spinning rust or higher powered USB3 media.
>>> 
>>> I view the power supply that I use as just giving a little
>>> more margin,  not as a way to increase what the devices
>>> total to.
>>> 
>>>> . . . I'm not sure what's considered "high powered" but the Samsung tech specs say this particular model uses 5.7 W on average and 10.0 W maximum. But it does seem curious that the Raspberry PI OS will boot this disk without issue, so I don't think it's the drive. I also tried a Samsung 950 PRO using a different enclosure (QNINE NVME Enclosure, M.2 PCIe SSD (M Key) to USB 3.0 External Case), but it behaved the same.
>>> . . .
>>> 
>>> Then you need to use a powered hub for that device.
>> 
>> I should have just referred to independent power. You
>> had written:
>> 
>> QUOTE
>> I'm trying to use a SAMSUNG (MZ-V7E500BW) 970 EVO SSD 500GB - M.2 NVMe, attached via the Geekworm X872 M.2 NVMe 2280/2260/2242/2230 SSD Expansion Board.
>> END QUOTE
>> 
>> https://geekworm.com/products/raspberry-pi-4-x872-m-2-nvme-2280-2260-2242-2230-ssd-expansion-board
>> 
>> shows that it has its own power connector and has an image
>> that says "please power x872 via DC Jack of XH2.54 connector
>> if SSD is not recognized or low power". Later text on the
>> page says:
>> 
>> QUOTE
>> Specifications:
>> Power Supply
>> 	• 5Vdc +/-5% , Powered by Raspberry Pi USB port
>> 	• 5Vdc via DC power jack or XH2.5 connector, Extra power for the SSD
>> END QUOTE
>> 
>> So, if I gather right, you need to connect a power
>> supply to the X872 and another to the RPi4B.
>> 
>> Another image says "Note: NOT recommended to use SAMSUNG SSD,
>> if use SAMSUNG SSD, please close WiFi". Later text on the page
>> says the same.
> 
> A-ha, indeed. I just noticed that as well. I've gone ahead and ordered a supplementary power supply and a lower-power NVMe to do more testing. I'll send an update once I've received and tested them.
> 
> Thank you for hopefully pointing me in the right direction.

Alright, so, I ended up buying a WDS500G2B0C, which seems to only use a maximum of 75 mW (this seems ... low, to say the least, but the column is unlabeled in the spec sheet I found here https://documents.westerndigital.com/content/dam/doc-library/en_us/assets/public/western-digital/product/internal-drives/wd-blue-nvme-ssd/product-brief-wd-blue-sn550-nvme-ssd.pdf). Sadly, it also would not boot from either of my NVMe-USB adapters.

After a while of getting frustrating forgetting which combination of image + usb adapter + drive configuration I had or hadn't tried, I thought to myself.. what would happen if I tried one of the USB2 ports? Bingo! It booted FreeBSD no problem.

So I'm not sure what exactly that means, except that I know the power/usb adapter/drive/image is not the issue. I don't think I really "need" the performance improvement of the USB3 port at the moment, but maybe that's something that will help troubleshoot the issue? It would certainly be nice to use little USB bridge pcb "cable" to have a neater installation though.

Any ideas?


>> https://www.raspberrypi.org/documentation/hardware/raspberrypi/power/README.md
>>> lists:
>>> 
>>> "Maximum total USB peripheral current draw" as: 1.2A ,
>>> which at 5.1V is 6W.
>>> 
>>> That figure is the total for all USB devices attached
>>> that are not powered independently.
>>> 
>>> That document also says that a 5.1V supply is required,
>>> not 5V.
>>> 
>>> The power supply that the RPi folks supply is 5.1V _at_ 3A
>>> or 15.3W. Even the 5.1V 3.5A power supply that I use
>>> only multiplies out to 17.85W.
>> 
>> ===
>> Mark Millard
>> marklmi at yahoo.com
>> ( dsl-only.net went
>> away in early 2018-Mar)
>> 
>> 
>> 
>> ===
>> Mark Millard
>> marklmi at yahoo.com
>> ( dsl-only.net went
>> away in early 2018-Mar)
Received on Fri Jun 11 2021 - 00:22:00 UTC

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