Lxw2015 wrote: ↑
Sun Sep 27, 2020 6:32 pm
W. H. Heydt wrote: ↑
Sat Sep 26, 2020 7:36 pm
Lxw2015 wrote: ↑
Sat Sep 26, 2020 7:25 pm
thanks for you all.
I think boot from USB OTP should be set by default. it's no harm. and made life easier.
It is...on the Pi3B+.
Bear in mind that the Pi2Bv1.2 uses the same SoC as the Pi3B/Pi3B+ (I believe that both the Pi3B and Pi2Bv1.2 have migrated to the BCM2837B0, which started out on just the Pi3B+) so the bit can be set on those boards, as well. It's just that nobody seems to expect to boot any version of Pi2B directly from a USB MSD.
I'm not quite understand what you mean. for Pi2B, if you don't expect boot from USB MSD, then just insert SD card into Pi2B. then it boot from SD card.
When the Pi2B was released--now known as the Pi2Bv1.1--it used the BCM2836 SoC. That SoC does not contain boot from USB MSD code at all. It can do "hybrid" booting, where part of what is need is on an SD card and the rest on on a USB MSD. As a cost saving issue, the Pi2B was updated to use the BCM2837 SoC--the one used on the Pi3B--and the newer version is the Pi2Bv1.2. Because the Pi2Bv1.2 uses the same SoC as the Pi3B, it contains the ROM code to boot from a USB attached MSD and once you set the OTP bit, it will do so. This is a part of why knowing *which* Pi2B you're looking at matters.
What it amounts to is that the Pi2Bv1.2 is a slower (900MHz, default) version of the Pi3B, without on-board WiFi. This is not something that appeals to everybody, but there are some good uses for it. At least, I think there are some good uses for it.
I've never heard of anyone actually do USB MSD booting on a Pi2Bv1.2, but I feel that it is important to remember that it *can* be done.
Perhaps some day, I'll do it...just so I can say that it's been done....