root@AP550:/tmp# cat /proc/mtd
dev: size erasesize name
mtd0: 00030000 00001000 "0:SBL1"
mtd1: 00010000 00001000 "0:MIBIB"
mtd2: 00010000 00001000 "0:BOOTCONFIG"
mtd3: 00010000 00001000 "0:BOOTCONFIG1"
mtd4: 000a0000 00001000 "0:QSEE"
mtd5: 000a0000 00001000 "0:QSEE_1"
mtd6: 00010000 00001000 "0:DEVCFG"
mtd7: 00010000 00001000 "0:DEVCFG_1"
mtd8: 00010000 00001000 "0:CDT"
mtd9: 00010000 00001000 "0:CDT_1"
mtd10: 00010000 00001000 "0:APPSBLENV"
mtd11: 000a0000 00001000 "0:APPSBL"
mtd12: 000a0000 00001000 "0:APPSBL_1"
mtd13: 00080000 00001000 "0:ART"
mtd14: 00080000 00020000 "0:TRAINING"
mtd15: 03e00000 00020000 "rootfs"
mtd16: 03e00000 00020000 "rootfs_1"
mtd17: 00439e80 0001f000 "kernel"
mtd18: 00382000 0001f000 "wifi_fw"
mtd19: 00005000 0001f000 "bt_fw"
mtd20: 00ec6000 0001f000 "ubi_rootfs"
mtd21: 01de9000 0001f000 "rootfs_data"
root@AP550:/tmp# sysupgrade -v -c nand-ipq5018-apps.img
Warning: optional section "sbl1" missing from "nand-ipq5018-apps.img". Continue...
Warning: optional section "sbl2" missing from "nand-ipq5018-apps.img". Continue...
Warning: optional section "u-boot" missing from "nand-ipq5018-apps.img". Continue...
Warning: optional section "lkboot" missing from "nand-ipq5018-apps.img". Continue...
Warning: optional section "ddr-ap-mp03.5-c1" missing from "nand-ipq5018-apps.img". Continue...
Warning: optional section "ssd" missing from "nand-ipq5018-apps.img". Continue...
Warning: optional section "tz" missing from "nand-ipq5018-apps.img". Continue...
Warning: optional section "rpm" missing from "nand-ipq5018-apps.img". Continue...
[ 1251.162990] sh (5066): drop_caches: 3
stat: No such file or directory
Saving config files...
etc/config/cert
etc/config/cnss_diag
etc/config/ddns
etc/config/dhcp
etc/config/dhcrelay
etc/config/dropbear
etc/config/ecm
etc/config/firewall
etc/config/login
etc/config/luci
etc/config/mcproxy
etc/config/mcsd
etc/config/multiwan
etc/config/network
etc/config/nss
etc/config/qcacfg80211
etc/config/router/dhcp
etc/config/router/firewall
etc/config/router/network
etc/config/router/wireless
etc/config/rpcd
etc/config/skb_recycler
etc/config/ssid-steering
etc/config/sysstat
etc/config/system
etc/config/system_4019
etc/config/thermal
etc/config/ubootenv
etc/config/ucitrack
etc/config/uhttpd
etc/config/upnpd
etc/config/wireless
etc/dnsmasq.conf
etc/dropbear/dropbear_rsa_host_key
etc/firewall.user
etc/fw_env.config
etc/group
etc/hosts
etc/inittab
etc/iproute2/rt_tables
etc/mcproxy.conf
etc/opkg.conf
etc/opkg/customfeeds.conf
etc/opkg/keys/141c3812dfd4eb4f
etc/opkg/keys/53bad1233d4c98c5
etc/opkg/keys/de98a2dd1d0f8a07
etc/passwd
etc/profile
etc/protocols
etc/rc.local
etc/services
etc/shadow
etc/shells
etc/ssl/openssl.cnf
etc/sysctl.conf
etc/sysstat/sysstat
etc/sysstat/sysstat.ioconf
etc/sysupgrade.conf
etc/uhttpd.crt
etc/uhttpd.key
lib/wifi/wifi_nss_hk_olnum
lib/wifi/wifi_nss_olcfg
lib/wifi/wifi_nss_olnum
etc/uhttpd.key
etc/uhttpd.crt
Command failed: Method not found
Command failed: Method not found
Sending TERM to remaining processes ... cnssdaemon uhttpd breakpad_report logd rpcd acfg_tool netifd mcsd [ 1252.310126] mc_detach: disabled snooping on br-lan
mcastds: Leaving mcsd executive program
ntpd thermald dnsmasq rngd sleep sleep qrtr-ns web_agent
Sending KILL to remaining processes ... rngd sleep sleep ping
Switching to ramdisk...
[ 1257.135333] UBIFS (ubi0:4): background thread "ubifs_bgt0_4" stops
Performing system upgrade...
Section script ignored
[ 1259.458765] ubi0 error: ubi_detach_mtd_dev: ubi0 reference count 2, destroy anyway
[ 1259.580962] ubi0: detaching mtd15
[ 1259.582306] ubi0: mtd15 is detached
ubiformat: mtd16 (nand), size 65011712 bytes (62.0 MiB), 496 eraseblocks of 131072 bytes (128.0 KiB), min. I/O size 2048 bytes
libscan: scanning eraseblock 495 -- 100 % complete
ubiformat: 496 eraseblocks have valid erase counter, mean value is 114
ubiformat: flashing eraseblock 190 -- 100 % complete
ubiformat: formatting eraseblock 495 -- 100 % complete
Flashed ubi-4049e62fbbe3d07598c224c9fe02ea661d241624
grep: /sys/block/mmcblk*/mmcblk*p*/uevent: No such file or directory
[ 1271.707689] ubi0: attaching mtd16
[ 1271.902742] ubi0: scanning is finished
[ 1271.919012] gluebi (pid 5641): gluebi_resized: got update notification for unknown UBI device 0 volume 4
[ 1271.919050] ubi0: volume 4 ("rootfs_data") re-sized from 1 to 247 LEBs
[ 1271.930635] ubi0: attached mtd16 (name "rootfs_1", size 62 MiB)
[ 1271.933888] ubi0: PEB size: 131072 bytes (128 KiB), LEB size: 126976 bytes
[ 1271.939703] ubi0: min./max. I/O unit sizes: 2048/2048, sub-page size 2048
[ 1271.946687] ubi0: VID header offset: 2048 (aligned 2048), data offset: 4096
[ 1271.953529] ubi0: good PEBs: 496, bad PEBs: 0, corrupted PEBs: 0
[ 1271.960292] ubi0: user volume: 5, internal volumes: 1, max. volumes count: 128
[ 1271.966529] ubi0: max/mean erase counter: 218/115, WL threshold: 4096, image sequence number: 1377334676
[ 1271.973625] ubi0: available PEBs: 0, total reserved PEBs: 496, PEBs reserved for bad PEB handling: 20
[ 1271.983248] ubi0: background thread "ubi_bgt0d" started, PID 5642
[ 1272.008305] gluebi (pid 5641): gluebi_create: gluebi MTD device 20 form UBI device 0 volume 3 already exists
UBI device number 0, total 496 LEBs (62980096 bytes, 60.1 MiB), available 0 LEBs (0 bytes), LEB size 126976 bytes (124.0 KiB)
Flashed wifi_fw_ipq5018_qcn6122cs-9d02e4d1248a1e369e0fcf4768eb71fbc49db4ab
Section wifi_fw_ipq5018_qcn9000-013aaac13b0b63d467720a0084be93d34b6303ae ignored
Section wifi_fw_ipq5018_qcn9000_qcn6122-482807a4325a85d1863d2c79e4de4fe98726914f ignored
Unlocking /dev/mtd2 ...
Erasing /dev/mtd2 ...
336+0 records in
336+0 records out
336 bytes (336B) copied, 0.003882 seconds, 84.5KB/s
Writing from <stdin> to /dev/mtd2 ...
Unlocking /dev/mtd3 ...
Erasing /dev/mtd3 ...
336+0 records in
336+0 records out
336 bytes (336B) copied, 0.001144 seconds, 286.8KB/s
Writing from <stdin> to /dev/mtd3 ...
> [ 1276.574423] ubi: mtd16 is already attached to ubi0ubiattach: error!: cannot attach "/dev/mtd16"
> error 17 (File exists)
> mount: mounting ubi0:rootfs_data on /tmp/overlay failed: Resource busy
> umount: can't unmount /tmp/overlay: Invalid argument
Upgrade completed
Rebooting system...
The error is that cannot mount ubi0:rootfs_data to /tmp/overlay at platform_copy_config funciton.