Ok, so I actually took the plunge and tried option 2 above, as follows (it appears the backport-kernel was updated from 5.2.9-2 to 5.2.17-1 overnight):
1. sudo vi /usr/share/flash-kernel/db/all.db -> /219 -> line 1447: change Mtd-Kernel: Kernel to Mtd-Kernel: RootFS2 2. sudo aptitude -t buster-backports -> Upgrade all Upgradable Packages -> Kernel is flashed to mtd3: Processing triggers for flash-kernel (3.99) ... kirkwood-qnap: machine: QNAP TS219 family Using DTB: kirkwood-ts219-6282.dtb Installing /usr/lib/linux-image-5.2.0-0.bpo.3-marvell/kirkwood-ts219-6282.dtb into /boot/dtbs/5.2.0-0.bpo.3-marvell/./kirkwood-ts219-6282.dtb Taking backup of kirkwood-ts219-6282.dtb. Installing new kirkwood-ts219-6282.dtb. flash-kernel: installing version 5.2.0-0.bpo.3-marvell flash-kernel: appending /usr/lib/linux-image-5.2.0-0.bpo.3-marvell/kirkwood-ts219-6282.dtb to kernel Generating kernel u-boot image... done. Flashing kernel (using 2170954/3145728 bytes)... done. Flashing initramfs (using 6568944/9437184 bytes)... done. Processing triggers for initramfs-tools (0.133+deb10u1) ... update-initramfs: Generating /boot/initrd.img-5.2.0-0.bpo.3-marvell kirkwood-qnap: machine: QNAP TS219 family Using DTB: kirkwood-ts219-6282.dtb Installing /usr/lib/linux-image-5.2.0-0.bpo.3-marvell/kirkwood-ts219-6282.dtb into /boot/dtbs/5.2.0-0.bpo.3-marvell/./kirkwood-ts219-6282.dtb Taking backup of kirkwood-ts219-6282.dtb. Installing new kirkwood-ts219-6282.dtb. Installing /usr/lib/linux-image-5.2.0-0.bpo.3-marvell/kirkwood-ts219-6282.dtb into /boot/dtbs/5.2.0-0.bpo.3-marvell/./kirkwood-ts219-6282.dtb Taking backup of kirkwood-ts219-6282.dtb. Installing new kirkwood-ts219-6282.dtb. flash-kernel: installing version 5.2.0-0.bpo.3-marvell flash-kernel: appending /usr/lib/linux-image-5.2.0-0.bpo.3-marvell/kirkwood-ts219-6282.dtb to kernel Generating kernel u-boot image... done. Flashing kernel (using 2170954/3145728 bytes)... done. Flashing initramfs (using 6568918/9437184 bytes)... done. 3. sudo fw_setenv bootcmd "uart1 0x68;cp.l 0xf8d00000 0x800000 0xc0000;cp.l 0xf8400000 0xb00000 0x240000;bootm 0x800000" sudo fw_setenv bootargs "console=ttyS0,115200 root=/dev/ram initrd=0xb00000,0x900000 ramdisk=34816" 4. sudo shutdown -r now Take a deep breath, and voila, it's ALIVE: $ cat /proc/version Linux version 5.2.0-0.bpo.3-marvell (debian-ker...@lists.debian.org) (gcc version 8.3.0 (Debian 8.3.0-6)) #1 Debian 5.2.17-1~bpo10+1 (2019-09-30) It seems to be working so far, although there is this message during bootup: [ 1.269790] Loading compiled-in X.509 certificates [ 1.326675] ------------[ cut here ]------------ [ 1.331358] WARNING: CPU: 0 PID: 1 at crypto/rsa-pkcs1pad.c:539 pkcs1pad_verify+0x38/0x10c [ 1.339661] Modules linked in: [ 1.342733] CPU: 0 PID: 1 Comm: swapper Not tainted 5.2.0-0.bpo.3-marvell #1 Debian 5.2.17-1~bpo10+1 [ 1.351912] Hardware name: Marvell Kirkwood (Flattened Device Tree) [ 1.358204] random: fast init done [ 1.361639] [<c0016c0c>] (unwind_backtrace) from [<c0013768>] (show_stack+0x18/0x1c) [ 1.369431] [<c0013768>] (show_stack) from [<c0021bd8>] (__warn+0xe0/0xf8) [ 1.376345] [<c0021bd8>] (__warn) from [<c0021fcc>] (warn_slowpath_null+0x40/0x4c) [ 1.383956] [<c0021fcc>] (warn_slowpath_null) from [<c01f76e4>] (pkcs1pad_verify+0x38/0x10c) [ 1.392444] [<c01f76e4>] (pkcs1pad_verify) from [<c01fd6cc>] (public_key_verify_signature+0x210/0x2d8) [ 1.401809] [<c01fd6cc>] (public_key_verify_signature) from [<c01fedf8>] (x509_check_for_self_signed+0xf0/0x118) [ 1.412035] [<c01fedf8>] (x509_check_for_self_signed) from [<c01fe070>] (x509_cert_parse+0x198/0x1c8) [ 1.421304] [<c01fe070>] (x509_cert_parse) from [<c01fea40>] (x509_key_preparse+0x1c/0x17c) [ 1.429701] [<c01fea40>] (x509_key_preparse) from [<c01fc688>] (asymmetric_key_preparse+0x68/0xc4) [ 1.438712] [<c01fc688>] (asymmetric_key_preparse) from [<c01c876c>] (key_create_or_update+0x144/0x378) [ 1.448156] [<c01c876c>] (key_create_or_update) from [<c0573c04>] (load_system_certificate_list+0xb4/0x11c) [ 1.457954] [<c0573c04>] (load_system_certificate_list) from [<c000ab2c>] (do_one_initcall+0x60/0x19c) [ 1.467309] [<c000ab2c>] (do_one_initcall) from [<c05601a8>] (kernel_init_freeable+0x214/0x264) [ 1.476056] [<c05601a8>] (kernel_init_freeable) from [<c041be00>] (kernel_init+0x10/0xf4) [ 1.484278] [<c041be00>] (kernel_init) from [<c00090e0>] (ret_from_fork+0x14/0x34) [ 1.491884] Exception stack(0xdf4c1fb0 to 0xdf4c1ff8) [ 1.496961] 1fa0: 00000000 00000000 00000000 00000000 [ 1.505177] 1fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 1.513398] 1fe0: 00000000 00000000 00000000 00000000 00000013 00000000 [ 1.520041] ---[ end trace 947abc38fbcd6ffd ]--- [ 1.524687] Problem loading in-kernel X.509 certificate (-22) But that's probably an issue for another bug report. Not sure if that's a workable solution for everyone, but at least I'm a happy camper now with the latest Linux kernel. Please DO NOT block further kernel upgrades from the QNAP TS-219 platform, even if the image size exceeds 2MB. Mine can take it :-) Best Regards, -Robert
