Extending a ext4 partition without losing data

umount /boot

parted /dev/sdb

(parted) print

Model: ATA Patriot Torqx 2 (scsi)
Disk /dev/sdb: 32.0GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos

Number Start End Size Type File system Flags
1 1049kB 12.9GB 12.9GB primary type=83
2 12.9GB 13.0GB 107MB primary ext4 type=83

(parted) rm 2

(parted) mkpart

Partition type? primary/extended? primary
File system type? [ext2]?
Start? 12.9GB
End? 13.4GB

(parted) quit

resize2fs /dev/sdb2

resize2fs 1.42.6 (21-Sep-2012)
Filesystem at /dev/sdb2 is mounted on /boot; on-line resizing required
old_desc_blocks = 1, new_desc_blocks = 2
The filesystem on /dev/sdb2 is now 498688 blocks long