Made E3 Flasher = PS3 downgrade easily

This article refers to the original NOR Flasher by E3 (this information only in passing, because there are cheap copies ...).
PS3 open, clip attach the NOR chip, read backup, patch on the PC, and play patched backup again - that the downgrade to 3:55 (or custom firmware). Also possible (but with soldering) is the operation of two different firmwares: for example Original and Custom in dual-boot mode. For this, however, one eSata station is still needed.
To disassemble the console and attach the clip there are countless videos on the net. Please inform in advance if your console is suitable (Super Slim is for example not supported).