Flashing OpenWrt onto the Cisco Meraki MR33 access point the hard way

Lately I got some used Cisco Meraki MR33 access points to upgrade my wireless network. Most of them came with a locked bootloader, which prevents me from flashing my own OpenWrt images, so removing the NAND and reprogramming it offline was necessary. This post documents the entire flashing process, some of the difficulties I dealt with, and provdes a simple replacement mounting bracket design for anyone who needs it.