Force recovery mode is like the first thing you need to know when it comes to flashing a Jetson device.
Check this guide:
First make sure whether you are using the A02 or B01 revision, and follow the instructions accordingly:
[J40] Carrier board rev A02 only: 8-pin button header; brings out several system
power, reset, and force recovery related signals (see the following diagram).
Pins 3 and 4 put the developer kit into Force Recovery Mode if they are
connected when it is powered on
[J50] Carrier Board Rev B01 only: 12-pin button header; brings out system power,
reset, UART console, and force recovery related signals:
Pins 9 and 10 put the developer kit into Force Recovery Mode if they are
connected when it is powered on
Basically, you shorten the two pins with a jumper, and plug in the power cable to put the device in force recovery mode.