zero mbr sgdisk 2

# dd if=/dev/urandom of=/dev/mmcblk1 bs=512 count=1 && echo -ne "\x55\xAA" | dd
of=/dev/mmcblk1 bs=1 seek=510
1+0 records in
1+0 records out
2+0 records in
2+0 records out
#
# sgdisk -p /dev/mmcblk1
Invalid partition data!
# sgdisk -og /dev/mmcblk1
Invalid partition data!
Information: Creating fresh partition table; will override earlier problems!

Warning! Mismatched GPT and MBR partition! MBR partition 1, of type 0x0D,
has no corresponding GPT partition! You may continue, but this condition
might cause data loss in the future!

Warning! Mismatched GPT and MBR partition! MBR partition 2, of type 0xF6,
has no corresponding GPT partition! You may continue, but this condition
might cause data loss in the future!

Warning! Mismatched GPT and MBR partition! MBR partition 3, of type 0x59,
has no corresponding GPT partition! You may continue, but this condition
might cause data loss in the future!

Warning! Mismatched GPT and MBR partition! MBR partition 4, of type 0x1E,
has no corresponding GPT partition! You may continue, but this condition
might cause data loss in the future!

Problem: MBR partitions 1 and 3 overlap!

Problem: MBR partitions 1 and 4 overlap!

Problem: MBR partitions 2 and 3 overlap!

Problem: MBR partitions 2 and 4 overlap!

Problem: MBR partitions 3 and 4 overlap!
[  384.334216]  mmcblk1: p1() p2(LNX) p3(MBR)
Warning! An error was reported when writing the partition table! This error
MIGHT be harmless, or the disk might be damaged! Checking it is advisable.