How can I move a working Raspbian Buster installation from Pi 3 to Pi 4?

Question

I have a Raspbian Buster working well on my Pi 3 B. How can I transfer this system to a new Pi 4? I don't want to reinstall everything, because I have a edited many system files. (It's wouldn't be as "easy" as (re-)installing 50 packages, and transferring /home. I'd also have to identify and copy the many changed system files, somehow.)

My troubleshooting

1. I've tested the new Pi with a freshly-downloaded Raspbian Buster Lite system, and can confirm that the new Pi is working.
2. I've tried simply moving the old card over, but the Pi won't boot. The ACT LED briefly flickers green (1–3 flickers for 1 second, then a sustained light for ~1 second), but then no light. I get no HDMI signal. (As a control, I've also tested without an SD card inserted. Here, the ACT LED flashes four times: three short and one long.)
3. I've thought perhaps that the newer boot partition from the fresh system was essential, so I tried rsyncing root from the old card into the new card's rootfs. However this also failed as per 2 above.

Answer 1

Had also the problem that my raspbian card from pi3 did not run in pi4 after upgrade to buster.

I found out that the install skript of bootloader and kernel do skip the installation of rpi4 support when there is not enough space on /boot/. My boot partition was around 100 Mb, its from the time when rpi2 was new. You can check the size of your partition with:

df -H

or

mount

you can also check if the install skript says you havn't enough space by reinstalling and checking the output of:

apt-get install --reinstall raspberrypi-bootloader* raspberrypi-kernel*

if you see the following output, you have the same Problem:

You do not have enough space in /boot to install this package.
Skipping Pi 4 support

To solve this problem i used a separate computer and changed the size of the /boot partition to at least 500Mb (usual size on other Linux) by the following steps. (assuming first partition is boot, second is root, using gparted for partion manipulation)

1. Backup whole SD

2. shrinking root Partition to the right to have free space for boot

3. copy content of boot partition to separate backupfolder

4. remember boot partition flags

5. delete and recreate boot partiton with the same filesystem in free space

6. set the partition flag from point 4

7. copy content of backupfolder (see point 3) into boot partion folder

8. check your /etc/fstab is still valid to boot (more to this following)

9. boot sdcard in rpi3 and reinstall "raspberrypi-bootloader* raspberrypi- kernel*"

10. boot sd in rpi4

my /etc/fstab did not reference /boot by uuid, if your fstab file has a entry like:

UUID=2e45-11ea /boot                       vfat    defaults,noatime        0 2

you need to change the uuid to the new uuid of the new boot partition. You can find the uuid in gparted under information. i had no problem with my /etc/fstab, it has this entry:

/dev/mmcblk0p1  /boot           vfat    defaults,noatime  0       2

Answer 2

If you can count those "flickers" they might give you a hint as to what is going wrong. There is a sticky on the raspberry pi forums that deals with Pis that won't boot. The link is https://www.raspberrypi.org/forums/viewtopic.php?f=28&t=58151. Note that there is a special section for RPi 4s. There's also a MagPi #60 troubleshooting guide that may help. That link is https://www.raspberrypi.org/magpi/issues/60/.

This weekend my RPi 4 wasn't booting. The ACT was blinking 4 times. According to the sticky that is a signal that the boot process couldn't find all the files on the SD card needed to boot. I hope that the sticky or the article helps you identify the problem.

Answer 3

I've thought perhaps that the newer boot partition from the fresh system was essential, so I tried rsyncing root from the old card into the new card's rootfs.

This is a horrible idea and while it may or may not explain why the system apparently doesn't get far boot-wise (depending on exactly how you did it), I certainly would not expect this to result in a working operating system, and if it did, I would not trust that installation.

What you should have done is copy the boot partition of the new buster install that works on the Pi 4 over (as in, replace the contents of) the one that doesn't. From the root partition then replace /lib/firmware/ and /lib/modules in the same direction (from working to non-working). This presumes the new image is really a new image created since the introduction of the Pi 4.

If that will boot on one Pi but not another, either:

1. You did it wrong.
2. The other Pi is busted.

So, if you can still boot the Pi with a different card, either it has a very peculiar defect, or you are stuck with door #1.

Answer 4

It is difficult to see what may be wrong. Here are some general tries I would start with. First make a working copy of your running installation and verify that the copy is still running on the RPi 3B. Only work with the copy.

Then I would use the serial debug console in the hope the kernel will tell me some errors before getting stuck. You have to purchase a serial to TTL adapter like this one https://www.amazon.com/ADAFRUIT-Industries-954-Serial-Raspberry/dp/B00DJUHGHI. There are much cheaper adapter from china and they are as good as that from adafruit but it takes weeks to get them. With a serial terminal program on your laptop you can manage the RasPi. On Linux I suggest to use tio /dev/ttyUSB0, that's made for this. On the RasPi you have to enable the serial console with enable_uart=1 in /boot/config.txt.

Then I would chroot into the copy and perform a full-upgrade in the hope it will update the latest firmware for the RPi 4B. So insert the copied SD Card into your portable card reader and attach it to the RPi 4B. Then boot it with Raspbian Buster Lite as you already have done. Now you should find the SD Card maybe on /dev/sda. Chroot to it:

rpi ~$ sudo -Es
rpi ~# mkdir /mnt/p2
rpi ~# mkdir /mnt/p2/boot
rpi ~# mount /dev/sda2 /mnt/p2
rpi ~# mount /dev/sda1 /mnt/p2/boot
rpi ~# cd /mnt/p2
rpi ~# mount --bind /proc proc
rpi ~# mount --bind /sys sys
rpi ~# mount --bind /dev dev
rpi ~# mount --bind /dev/pts dev/pts
rpi ~# mkdir run/udev
rpi ~# mount --bind /run/udev run/udev
rpi ~# LANG=C.UTF-8 chroot /mnt/p2 /bin/bash

rpi ~# apt update
rpi ~# apt full-upgrade

rpi ~# exit   # from chroot
rpi ~# umount proc
rpi ~# umount sys
rpi ~# umount dev/pts
rpi ~# umount dev
rpi ~# umount run/udev
rpi ~# exit    # from sudo

rpi ~$ sudo poweroff

Now boot with the upgraded SD Card. Good luck :-)

If it still doesn't work you can look at a very early bootup stage what debug messages the bootloader you give with the serial to TTL adapter. A Raspberry Pi 4B has its bootloader stored in an EEPROM so you can reflash it with another config. How to do it look at Raspberry Pi 4 boot EEPROM and in man rpi-eeprom-update. Here in short the steps I have tested. Get the default configuration:

rpi ~$ rpi-eeprom-config /lib/firmware/raspberrypi/bootloader/critical/pieeprom-2019-09-10.bin --out bootconf.txt

In bootconf.txt I set BOOT_UART=1 and cleaned up spaces behind the last entry and blank lines at the end. I don't know why they are there. To make a new image with the modified configuration and flash it then do:

rpi ~$ rpi-eeprom-config /lib/firmware/raspberrypi/bootloader/critical/pieeprom-2019-09-10.bin --config bootconf.txt --out pieeprom-new.bin
rpi ~$ sudo rpi-eeprom-update -d -f ./pieeprom-new.bin

Now on reboot I get this additional output on the serial console where it should be able to see where booting get stuck:

[ 1284.473982] reboot: Restarting system

PM_RSTS: 0x00001020
RPi: BOOTLOADER release VERSION:f626c772 Sep 10 2019 10:41:52 BOOTMODE: 0x00000006 part: 0 BUILD_TIMESTAMP=1568112110
uSD voltage 1.8V
GLOBAL_RESET

PM_RSTS: 0x00001000
RPi: BOOTLOADER release VERSION:f626c772 Sep 10 2019 10:41:52 BOOTMODE: 0x00000006 part: 0 BUILD_TIMESTAMP=1568112110
uSD voltage 3.3V
SD HOST: 200000000 CTL0: 0x00000000 BUS: 100000 Hz div: 2000 status: 0x1fff0000 delay-ticks: 1080
SD HOST: 200000000 CTL0: 0x00000f00 BUS: 100000 Hz div: 2000 status: 0x1fff0000 delay-ticks: 1080
CID: 001b534d3030303030107ce814ef00f3
CSD: 400e00325b590000775d7f800a400000
CSD: VER: 1 logical blocks: 30557 mult: 1024 rd(len: 512 partial: 0 misalign: 0) sectors: 31291392
SD: bus-width: 4 spec: 2 SCR: 0x02358003 0x00000000
SWITCH_FUNC: 0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000010000038001800180018001800180c800
SD HOST: 200000000 CTL0: 0x00000f04 BUS: 40000000 Hz div: 6 status: 0x1fff0000 delay-ticks: 2
MBR: 0x00002000,  258048 type: 0x0c
MBR: 0x00041000,31025152 type: 0x8e
MBR: 0x00000000,       0 type: 0x00
MBR: 0x00000000,       0 type: 0x00
part-offset: 8192 oem:  mkfs.fat volume:  BOOT
rsc: 32 sectors-per-fat: 1985 clusters: 254046 cluster-size: 1 root-dir: 2 root-sectors: 0
WEL: 0x00002fa2 0x00040fff
PM_RSTS: 0x00001000
Partition: 0
part-offset: 8192 oem:  mkfs.fat volume:  BOOT
rsc: 32 sectors-per-fat: 1985 clusters: 254046 cluster-size: 1 root-dir: 2 root-sectors: 0
Loading config.txt hnd: 0x0001596f
Initialising SDRAM 'Micron' 16Gb x1 total-size: 16 Gbit 3200
Loading recovery.elf hnd: 0x00000000
Failed to read recovery.elf error: 6
Loading start4.elf hnd: 0x00024d8f
Loading fixup4.dat hnd: 0x0002efda
MEM GPU: 76 ARM: 948 TOTAL: 1024
FIXUP src: 128 256 dst: 948 1024
Starting start4.elf @ 0xfec00200

Answer 5

To migrate a working Raspbian system from a Raspberry Pi 3 to a 4:

Assuming you're running Stretch and need to upgrade to Buster:

1. Back up your card
2. Update and upgrade: sudo apt update && sudo apt dist-upgrade -y
3. Edit repository sources: sudo nano /etc/apt/sources.list
   • Change "stretch" to "buster": deb http://raspbian.raspberrypi.org/raspbian stretch main contrib non-free rpi becomes deb http://raspbian.raspberrypi.org/raspbian buster main contrib non-free rpi
   • Also edit the entries in the .list files in /etc/apt/sources.list.d
4. Update and upgrade again: sudo apt update && sudo apt dist-upgrade
   • Notice I didn't add -y; this means you will have to babysit the upgrade a bit.
5. Clean up: sudo apt autoremove -y && sudo apt autoclean
6. Reboot

This should do it. These are modified instructions from https://pimylifeup.com. The only snag I ran into was having to add keys for a repository. It was a lot smoother than I expected.