THANK YOU!! I just made it boot (without u-boot ATM) with all 4GB RAM enabled. And my problem was my own stupidity. Several weeks ago, when researching why it wouldn't boot, I somewhere found the boot param "modprobe.blacklist=sdhci_iproc" which I added to my command.txt. Without that module, the microSD can't be read, of course. (IIRC, the website was about booting from SSD via USB since the USB port is faster than the MicroSD port on pre-4 models.) So after removing that part, the system started to come alive.
Now when doing apt update from the Pi4 itself, this came up: Processing triggers for flash-kernel (3.98ubuntu3) ... Unsupported platform. dpkg: error processing package flash-kernel (--configure): installed flash-kernel package post-installation script subprocess returned error exit status 1 Errors were encountered while processing: flash-kernel I had to add the proper entries for the RPi4 to /etc/flash-kernel/db and then that worked, too. It seems I can finally start to migrate my Pi 3 services to the newer (and faster) Pi 4. Awesome! Many thanks again for your help! Now looking forward to the u-boot with 4GB RAM support, then it's perfect. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1847163 Title: [FFe] Firmware bump for Pi 4 boot support To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-firmware-raspi2/+bug/1847163/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs