boot {part} not working on Pi4 (Noobs 3.2)

[matthuisman]

NOOBs Lite 3.2
https://downloads.raspberrypi.org/NOOBS_lite_latest

Current Behaviour
NOOBS ignores reboot {part} and does normal boot procedure (colour screen, noobs recovery etc)

Expected Behaviour
reboot {part} reboots straight into OS

Steps to reproduce

• Format SD card and copy over NOOBs 3.2 files
• Boot NOOBs and install Raspbian Lite
• Boot Raspbian
• Login (pi / raspberry)
• Run command: sudo reboot 6
• Observe NOOBS reboots into colour screen then NOOBS then Raspbian
• Should boot straight into Raspbian

Latest Raspbian Buster is running systemd 241
I tried the same Buster on Pi3B+ running same systemd and that works.
That makes me think that the issue isn't the reboot problem that was in systemd
systemd/systemd#11602

Notes

• autoboot.txt still works correctly
• same exact steps above work on Pi3B+

[matthuisman]

cc @procount (also same with latest PINN)

If I remember correctly, the reboot {part} stuff is actually inside the Raspberry Pi firmware?

[XECDesign]

This isn't a NOOBS issue, but a systemd issue. It may be fixed in Debian's next point release, but I'm not sure.

I've reported it here a while back: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=928659

[matthuisman]

ok, looks like it was merged into systemd here:
systemd/systemd#11602

I suspect it may never find it's way into buster?
So probably best I start looking for a work-around.

My main requirement is it working in LibreELEC.
For my noobs companion add-on to easily boot into other installed OS's.

I do have a a bit of reboot code I use on systems that didn't support reboot {params}
https://github.com/matthuisman/plugin.program.noobs.companion/blob/master/resources/files/part_reboot.c

So maybe I can use that for now on these.
However, not sure how to do a tidy shutdown before the syscall.

UPDATE

I've done same tests in LibreELEC across both boards and the fault is only on RPI4.

LibreELEC 9.1.002 Pi3B+ (systemd version 242)
reboot 6 - works

LibreELEC 9.1.002 Pi4 (systemd version 242)
reboot 6 - doesn't work

Same results with latest master builds from here:
http://milhouse.libreelec.tv/builds/master/

I also tried my reboot_part code which bypasses systemctl and uses the syscall with LINUX_REBOOT_CMD_RESTART2 and that only works on Pi3B+

I also tried Raspbian Buster on Pi3B+ (systemd version 241) and reboot 6 works as well.
So, that's good news - appears Buster does have a working systemd.

Leads me to believe that it is broken somewhere in Raspberry Pi 4 firmware?

[XECDesign]

Alright, might be another issue then. I'll check.

[XECDesign]

The fix to the issue I thought this was was introduced in 241-4, so yes, it's definitely a part of Raspbian now.

Sorry, I completely forgot about this, but you can't reboot into different partitions when the uSD interface is running on 1.8V (UHS). You need to boot with sdhci.debug_quirks2=4 in cmdline.txt for it to work, but it will sacrifice SD speed (I don't know how much).

AIUI, the issue is that once the card is in UHS mode, we can't get out of it without resetting power, losing the content of the reset register (which contains the reboot partition number). Due to reasons I don't quite understand, we can't continue in UHS mode and must switch to 3.3V to properly initialise the card.

[lurch]

Background info about the bewildering array of different SD card modes https://en.wikipedia.org/wiki/SD_card#Ultra_High_Speed_(UHS)

ping @procount as he'll probably find this thread useful for PINN 😉

[matthuisman]

Interesting. So the Pi3B+ doesn't use UHS?

…

On Wed, 28 Aug 2019, 10:55 PM Andrew Scheller, ***@***.***> wrote: Background info about the bewildering array of different SD card modes https://en.wikipedia.org/wiki/SD_card#Ultra_High_Speed_(UHS) ping @procount <https://github.com/procount> as he'll probably find this thread useful for PINN 😉 — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#551?email_source=notifications&email_token=ABPQAKPG6ZDANHATK2W4E23QGZKSDA5CNFSM4IPY52RKYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOD5KW4EQ#issuecomment-525692434>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ABPQAKPLM5IMOLFRMFNRYMLQGZKSDANCNFSM4IPY52RA> .

[XECDesign]

Correct, prior to the pi 4, we didn't do UHS switching.

[matthuisman]

So the cmdline quirk just goes in the noobs cmdline? Or will each OS need it? If just in noobs, then the slowdown would only be in noobs itself?

…

On Thu, 29 Aug 2019, 2:24 AM XECDesign, ***@***.***> wrote: Correct, prior to the pi 4, we didn't do UHS switching. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#551?email_source=notifications&email_token=ABPQAKPZ3KRUNJ63R5WQZI3QG2DCTA5CNFSM4IPY52RKYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOD5LJVKQ#issuecomment-525769386>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ABPQAKNRI4PMQYIBCZXBSYDQG2DCTANCNFSM4IPY52RA> .

[XECDesign]

It needs to into cmdline.txt for each partition you'd like to reboot from/through. If at any point it goes into UHS mode, you'll lose the ability to reboot into other partitions.

By default, we only add it to NOOBS itself, which is why rebooting into different partitions works from NOOBS, but not after booting into an OS without the quirk set.

[matthuisman]

Oh thats a shame :( Noobs would probably enjoy UHS speeds when installing OS's etc. Do you think a fix is likely? Eg. Storing reboot param elsewhere that can survive the power loss. Or, can you think of any work around? I was thinking writing to autoboot but then no way to remove it once booted. Maybe a one shot file could be added? Works same as autoboot, but only once (eg. Removed after used) Or maybe a software solution in noobs where it could be told to autoboot an os (as quickly as possible) Noobs reads file then does reboot to partition. No recovery etc. Won't be as quick as reboot param but still something.

…

On Thu, 29 Aug 2019, 2:47 AM XECDesign, ***@***.***> wrote: It needs to into cmdline.txt for each partition you'd like to reboot from/through. If at any point it goes into UHS mode, you'll lose the ability to reboot into other partitions. By default, we only add it to NOOBS itself, which is why rebooting into different partitions works from NOOBS, but not after booting into an OS without the quirk set. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#551?email_source=notifications&email_token=ABPQAKIX4EJTSQZ5KRKETBDQG2FWJA5CNFSM4IPY52RKYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOD5LMBLQ#issuecomment-525779118>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ABPQAKJKEQQSRY7UQ7ZGEO3QG2FWJANCNFSM4IPY52RA> .

[XECDesign]

The only two places that would survive power loss (that I know of) are the EEPROM and the SD Card.

It can't be the SD card because we can't write to it when it's booted straight into UHS mode. At least not in any way that we think is safe.

It can't be the EEPROM because it will complicate the bootloader and waste write cycles.

[procount]

ping @procount as he'll probably find this thread useful for PINN 😉

Now that I am reminded, I remember XECDesign mentioning this issue to me when I was first adapting for the Pi4.

Oh thats a shame :(
Noobs would probably enjoy UHS speeds when installing OS's etc.

@matthuisman - Some idea of the speed difference would be interesting....

Or maybe a software solution in noobs where it could be told to autoboot an
os (as quickly as possible)

From what I understand from @XECDesign 's remarks, no matter what software solution you put in place to circumvent this, you still need to pull the power to allow the SD card to switch out of UHS mode. i.e even modifying autoboot.txt (or similar) won't work unless you pull the power to cause the reboot - is that correct?

[XECDesign]

Not pull the power in the sense that you need to unplug it. Just that when the bootloader starts and detects that it's in UHS mode, it will reset itself in a way that clears the reset register.

If you wanted to, you could drop a file somewhere and have PINN look at it and then delete it. Of course that would be much slower, since it would have to go through PINN. You could drop autoboot.txt and then delete it on next boot, but that would be up to each OS you boot into. Not sure that I can think of many other alternatives.

[lurch]

Not pull the power in the sense that you need to unplug it. Just that when the bootloader starts and detects that it's in UHS mode, it will reset itself in a way that clears the reset register.

Ahhh, I was wondering if that was the case, because otherwise a 'sudo reboot' wouldn't work from a regular image-install of Raspbian either 😉

You could drop autoboot.txt and then delete it on next boot, but that would be up to each OS you boot into.

Yeah, that's what I was thinking too, but you'd probably also want some other "marker file" indicating that this is only a "temporary" autoboot.txt which should be auto-deleted, to prevent "normal" usages of autoboot.txt being deleted automatically. (IYSWIM!)