LVM2 partition previously began on sector 2048

Offset 1048576 = 2048 * 512

dmsetup table shows where LV begins, usually at offset 2048 (unit=sectors), -> new partition starts at sector 4096!

Don't forget to update-grub (check root=UUID=<uuid of ext4>) and grub-install /dev/vda after making these changes!

# fdisk -l
Disk /dev/vda: 32 GiB, 34359738368 bytes, 67108864 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x5b446ef5

Device     Boot Start      End  Sectors Size Id Type
/dev/vda1        4096 67108863 67104768  32G 83 Linux

# Overwrite LVM2 header

# hexdump -C /dev/vda -s 1048576 -n 2048
00100000  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
00100200  4c 41 42 45 4c 4f 4e 45  01 00 00 00 00 00 00 00  |LABELONE........|
00100210  37 d8 9c 27 20 00 00 00  4c 56 4d 32 20 30 30 31  |7..' ...LVM2 001|
00100220  4a 32 55 32 6e 4e 59 31  6f 4c 50 76 69 6a 48 46  |J2U2nNY1oLPvijHF|
00100230  42 54 6b 52 42 76 33 4f  73 58 6e 37 32 4f 51 46  |BTkRBv3OsXn72OQF|
00100240  00 00 f0 ff 07 00 00 00  00 00 10 00 00 00 00 00  |................|
00100250  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00100260  00 00 00 00 00 00 00 00  00 10 00 00 00 00 00 00  |................|
00100270  00 f0 0f 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00100280  00 00 00 00 00 00 00 00  01 00 00 00 00 00 00 00  |................|
00100290  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
00100800

# dd if=/dev/zero of=/dev/vda seek=1048576 bs=1 count=1024 conv=notrunc                                                                                                                                          1024+0 records in
1024+0 records out
1024 bytes (1.0 kB) copied, 0.00233243 s, 439 kB/s
root@playground ~ # hexdump -C /dev/vda -s 1048576 -n 2048
00100000  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
00100800

# resize2fs /dev/vda1
resize2fs 1.42.12 (29-Aug-2014)
Filesystem at /dev/vda1 is mounted on /; on-line resizing required
old_desc_blocks = 1, new_desc_blocks = 2
The filesystem on /dev/vda1 is now 8388096 (4k) blocks long.

root@playground ~ # df
Filesystem     1K-blocks    Used Available Use% Mounted on
/dev/vda1       32894832 1070876  30381616   4% /