Dennis Lee Bieber <dennis.l.bie...@gmail.com> wrote: > > I'm surprised this post even came through. The beagleboard forum > /moved/ to a new web-based-only system (which I have refused to fight with
I suspect this will carry on working. :-) Good! > -- I tried but found it cryptic and unusable for someone accustomed to > newsreader clients which fetch all messages in a batch and permit later > responses to be made; I abhor web-based "fetch one message, make a reply, > send, fetch next message") > > The Google Groups forum has been abandoned. > > On Wed, 1 Sep 2021 16:50:11 +0100, in gmane.comp.hardware.beagleboard.user > Chris Green <cl-rxdkphot...@public.gmane.org> wrote: > > >If one has a BBB which normally boots from eMMC is it possible to > >write a script that will reboot from the microSD card? > > > > On current Beagle systems, it is u-Boot which determines the boot > device dynamically. > > That is: > > By default the u-Boot in the eMMC starts processing > > It then scans for a bootable uSD card > > If a valid uSD card is found, it toggles the boot device to > be the > uSD card, and proceeds to load the configuration from the uSD card; > otherwise it continues to load the configuration from the eMMC > > If there is no u-Boot (and maybe other files) found on the eMMC, the > SoC [hardware] boot sequence is to look for a valid uSD card and load > u-Boot from that card. > > The end state: if a bootable uSD card exists, it automatically becomes > the booted image, skipping the rest of the eMMC (u-Boot comes from the > first version found: eMMC then uSD). > > Prior to this form of u-Boot, one was required to hold down the > boot-select button on the BBB to force uSD card load. But that form of > u-Boot vanished near the end of the Wheezy era (Debian 7). This was also > the days of kernel loaded device tree overlays -- u-Boot loaded overlays > came in during the Jessie (Debian 8) era. The two u-Boots are totally > INCOMPATIBLE with Debian versions of the other style (Wheezy u-Boot does > not load DTOs, but Jessie and later Debian kernels expect to find the DTOs > already loaded). > > I don't know enough about u-Boot and uEnv.txt to know if there is some > way to modify uEnv.txt to /not/ transfer control to the uSD card except > when you want to do you back-up stuff. > OK, thanks, I suspect it may be rather more difficult than I had hoped. What I'm aiming for is a Pi/BBB type system that can clone itself automatically every day or so. That would allow me to have a fairly quick to implement backup for my Pi (could justas well be a BBB) that provides DHCP/DNS on my LAN. -- Chris Green ยท -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/9jv40i-u7eg1.ln1%40esprimo.zbmc.eu.
