I got a CI40 dev board from this Kickstarter https://www.kickstarter.com/projects/imgtec/creator-ci40-the-ultimate-iot-in-a-box-dev-kit .
Didn't have a chance to try it until now, and looks like it already has a corrupt flash memory (out of the box). Flashing /dev/mtd5 with ubiformat gives me error "ubiformat: 6 bad eraseblocks found, numbers: 512, 513, 1020, 1021, 1022, 1023" and after that booting says "Error reading superblock on volume 'ubi:rootfs' errno=-22!". I switched back partitions to get back to Linux. Is there any way to remap the corrupt blocks or somehow work around the problem?