I have a Pogoplug V4 A3 01 with serial port, with very recent uBoot and a running OpenWRT in flash. I have now spent a very long time building a boot USB for Debian following the countless recipes posted on this forum. I also have a very old Raspberry running current Debian which I use for some of the building, but it is a different architecture frm the Pogo. First I spent a long time configuriby frankenstein3 - Debian