I’m trying ton install TWRP on my FP2, after factory reset with FPOS10 installed.
I use the menu line “Apply update from ADB” from the recovery mode.
My device is well founded by ADB.
I run from the command line of my PC in “platform-tools” :
adb sideload twrp-3.6.0_9-0-FP2.img
The error message is always “footer is wrong”, “Signature verification failed”, “error: 21”.
I even tried with 220.127.116.11 (wich I used before) or 18.104.22.168.
When I reboot to bootloader, the phone stays on the “FAIRPHONE” screen, with blue light blinking slowly, but I can do nothing more at this point. I must do a hard stop.