UPDATED (June 2021): 17-distro multi-boot image for Pinephone (incl. 3GiB variant)

[K_Research]

Hello I made it to this step in the instructions

sudo echo ", +" | sfdisk -n -N 2 /dev/sdb2
sfdisk: cannot open /dev/sdb2: Permission denied

And when I try the next command I get

sudo echo ", +" | sfdisk -N 2 /dev/sdb2
sfdisk: cannot open /dev/sdb2: Permission denied


Suggestions?

Thanks