When its red its means the payload of the dongle isn't loaded, which means games wont work (even old ones). The error in multiman was prolly BD-EMU not detected or whatever you may not be able to mount games or something like that just means dongle payload isnt loaded and CFW is not in TB mode but rather dongleless CFW 3.55 mode.
Not much to do except reboot like you did mine does the same. If you have an upgraded ps3 internal HD that may be the problem the bigger capacity internals like 500GB require more power at boot and the TB dongle also requires power so sometimes this happens. Best to unplug all USB devices except dongle and then after ps3 boots with green dongle plug in ext hd's, controllers etc
PS3 Slim 4.21.2 Rebug REX 4.31 Spoof (external 1TB/3TB), PS2 Fat w/ Internal HD