Hi All, We are using arm64, quad-core, with Linux Kernel 5.15 with 1GB NAND. We have A/B partitioning and around 9 ubi volumes. During boot-up we observed that the ubiattach alone is taking around 1.2 secs (either user space or kernel space). The snapshot of the log is shown below. I have tried using fastmap as well, but still no difference. Are there any other techniques to improve the ubiattach timing ? Logs: ---------- Doing from initramfs: {{{ [ 6.949143][ T214] ubi0: attaching mtd54 [ 8.023766][ T214] ubi0: scanning is finished [ 8.035901][ T214] ubi0: attached mtd54 (name "system", size 867 MiB) [ 8.042635][ T214] ubi0: PEB size: 262144 bytes (256 KiB), LEB size: 253952 bytes [ 8.050423][ T214] ubi0: min./max. I/O unit sizes: 4096/4096, sub-page size 4096 [ 8.058134][ T214] ubi0: VID header offset: 4096 (aligned 4096), data offset: 8192 [ 8.066011][ T214] ubi0: good PEBs: 3470, bad PEBs: 0, corrupted PEBs: 0 [ 8.072995][ T214] ubi0: user volume: 10, internal volumes: 1, max. volumes count: 128 [ 8.081225][ T214] ubi0: max/mean erase counter: 3/0, WL threshold: 4096, image sequence number: 302691963 [ 8.091242][ T214] ubi0: available PEBs: 0, total reserved PEBs: 3470, PEBs reserved for bad PEB handling: 80 [ 8.101544][ T215] ubi0: background thread "ubi_bgt0d" started, PID 215 UBI device number 0, total 3470 LEBs (881213440 bytes, 840.3 MiB), available 0 LEBs (0 bytes), LEB size 253952 bytes (248.0 KiB) [ 8.136907][ T227] block ubiblock0_0: created from ubi0:0(rootfs_a) }}} Doing from Kernel using cmdline: ubi.mtd=54,0,30 : {{{ [ 6.702817][ T1] ubi0: default fastmap pool size: 170 [ 6.702822][ T1] ubi0: default fastmap WL pool size: 85 [ 6.702826][ T1] ubi0: attaching mtd54 […] [ 7.784955][ T1] ubi0: scanning is finished [ 7.797135][ T1] ubi0: attached mtd54 (name "system", size 867 MiB) }}} Thanks, Pintu