Hi. I have recently upgraded to bullseye on my TS-220, and ran into the problem with the kernel no longer fitting into the allocated flash partition that are also documented on Martin's page here: http://www.cyrius.com/debian/kirkwood/qnap/ts-219/upgrade/ (what a great resource btw!)
I have now managed to install the bullseye kernel into the otherwise unused (?) "RootFS2" partition (3MB), so I thought I'd report on the steps I went through, in case it might be helpful to someone else. - installed libubootenv-tool - configured the fw_* tools by copying /usr/share/doc/u-boot-tools/examples/qnap_ts119-219.config to /etc/fw_env.config - made a backup of the U-Boot configuration using fw_printenv - made a backup of the flash as described on Martin's page For testing purposes, I then manually created a uImage of the buster kernel already installed and flashed it to "RootFS2", leaving the initramfs in "RootFS1" untouched. Then I used a serial cable to manually copy and boot the kernel from "RootFS2" in U-Boot, testing the bootargs/bootcmd modifications that would have to be made (see below). That worked just fine, so I went ahead with setting it up proper: - changed the partition that flash-kernel uses for the kernel by adding the following lines to /etc/flash-kernel/db: Machine: QNAP TS-119/TS-219 Machine: QNAP TS219 family Mtd-Kernel: RootFS2 - installed the current *-marvell kernel from bullseye, which did now succeed: Generating kernel u-boot image... done. Flashing kernel (using 2456450/3145728 bytes)... done. Flashing initramfs (using 4470940/9437184 bytes)... done. - modified the U-Boot environment to copy the "RootFS2" partition (0xf8d00000, 3MB) instead of "Kernel" (0xf8200000, 2MB). Accordingly, initrd also needed to be moved up by 1MB (to 0xb00000 instead of 0xa00000): $ fw_setenv bootargs "console=ttyS0,115200 root=/dev/ram initrd=0xb00000,0x900000" $ fw_setenv bootcmd "uart1 0x68;cp.l 0xf8d00000 0x800000 0xc0000;cp.l 0xf8400000 0xb00000 0x240000;bootm 0x800000" - rebooted. It worked :-) $ uname -r 5.10.0-8-marvell Cheers, Christian