Tested on x86 xenial-hwe. `update-initramfs` works and no ehci-platform in initrd. System works fine after reboot.
ubuntu@zwicky:~$ sudo update-initramfs -k all -u update-initramfs: Generating /boot/initrd.img-4.15.0-65-generic W: mdadm: /etc/mdadm/mdadm.conf defines no arrays. update-initramfs: Generating /boot/initrd.img-4.15.0-64-generic W: mdadm: /etc/mdadm/mdadm.conf defines no arrays. ubuntu@zwicky:~$ ls -al /boot total 131680 drwxr-xr-x 4 root root 4096 Sep 26 04:20 . drwxr-xr-x 23 root root 4096 Sep 26 04:15 .. -rw-r--r-- 1 root root 217381 Sep 13 11:11 config-4.15.0-64-generic -rw-r--r-- 1 root root 217370 Sep 18 11:06 config-4.15.0-65-generic drwxr-xr-x 3 root root 4096 Jan 1 1970 efi drwxr-xr-x 5 root root 4096 Sep 26 04:16 grub -rw-r--r-- 1 root root 54946864 Sep 26 04:20 initrd.img-4.15.0-64-generic -rw-r--r-- 1 root root 54945126 Sep 26 04:19 initrd.img-4.15.0-65-generic -rw------- 1 root root 4061501 Sep 13 11:11 System.map-4.15.0-64-generic -rw------- 1 root root 4062077 Sep 18 11:06 System.map-4.15.0-65-generic -rw------- 1 root root 8172440 Sep 17 19:28 vmlinuz-4.15.0-64-generic -rw------- 1 root root 8181016 Sep 19 08:08 vmlinuz-4.15.0-65-generic ubuntu@zwicky:~$ sudo dpkg -l | grep initramfs-tools-core ii initramfs-tools-core 0.122ubuntu8.15 all generic modular initramfs generator (core tools) ubuntu@zwicky:~/temp$ dd if=/boot/initrd.img-4.15.0-65-generic of=initrd.img bs=512 skip=4768; zcat initrd.img | cpio -i 102546+1 records in 102546+1 records out 52503910 bytes (53 MB, 50 MiB) copied, 0.17038 s, 308 MB/s 296093 blocks ubuntu@zwicky:~/temp$ ls bin conf etc init initrd.img lib lib64 run sbin scripts usr var ubuntu@zwicky:~/temp$ find . -name '*hci*' ./lib/modules/4.15.0-65-generic/kernel/drivers/mmc/host/sdhci-pci.ko ./lib/modules/4.15.0-65-generic/kernel/drivers/mmc/host/sdhci.ko ./lib/modules/4.15.0-65-generic/kernel/drivers/mmc/host/sdhci-xenon-driver.ko ./lib/modules/4.15.0-65-generic/kernel/drivers/mmc/host/sdhci-acpi.ko ./lib/modules/4.15.0-65-generic/kernel/drivers/mmc/host/sdhci-pltfm.ko ./lib/modules/4.15.0-65-generic/kernel/drivers/usb/host/xhci-plat-hcd.ko ./lib/modules/4.15.0-65-generic/kernel/drivers/ata/acard-ahci.ko ./lib/modules/4.15.0-65-generic/kernel/drivers/ata/ahci_platform.ko ./lib/modules/4.15.0-65-generic/kernel/drivers/ata/ahci.ko ./lib/modules/4.15.0-65-generic/kernel/drivers/ata/libahci_platform.ko ./lib/modules/4.15.0-65-generic/kernel/drivers/ata/libahci.ko ./lib/modules/4.15.0-65-generic/kernel/drivers/firewire/firewire-ohci.ko ubuntu@zwicky:~/temp$ uname -a Linux zwicky 4.15.0-65-generic #74~16.04.1-Ubuntu SMP Wed Sep 18 09:51:44 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to initramfs-tools in Ubuntu. https://bugs.launchpad.net/bugs/1842284 Title: initramfs does not copy ehci-platform Status in initramfs-tools package in Ubuntu: Fix Released Status in initramfs-tools source package in Xenial: Fix Committed Status in initramfs-tools source package in Bionic: Fix Released Status in initramfs-tools source package in Disco: Fix Released Status in initramfs-tools source package in Eoan: Fix Released Bug description: [Impact] If you install Ubuntu onto USB storage behind a Platform USB host controller, it will not be able to boot because the generated initramfs will not include the host controller driver. [Test Case] Install to a USB stick attached to platform USB controller and reboot. Booting will fail because it will be unable to find the root file system. [Regression Risk] Driver is only loaded when system requires ehci-platform, minimizing the impact to all other systems. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/initramfs-tools/+bug/1842284/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp