switch A for to port QSFP 49-50

>system - view
]int f1/0/49 
]shutdown
]int f1/0/50
]shutdown
]irf-port 1/1
]port group interface FortyGigE1/0/49
]port group interface FortyGigE1/0/50
]int f1/0/49
]undo shutdown
]int f1/0/50
]undo shutdown
]irf-port-configuration active
]irf auto-update enable

Switch B

>system - view
] irf member 1 renumber 2
] quit 
> reboot
>system - view
]int f2/0/49 
]shutdown
]int f2/0/50
]shutdown
]irf-port 2/2
]port group interface FortyGigE2/0/49
]port group interface FortyGigE2/0/50
]int f2/0/49
]undo shutdown
]int f2/0/50
]undo shutdown
]irf-port-configuration active
]irf auto-update enable

Switch A for to port QSFP 51-52

>system - view
]int f1/0/51 
]shutdown
]int f1/0/52
]shutdown
]irf-port 1/2
]port group interface FortyGigE1/0/51
]port group interface FortyGigE1/0/52
]int f1/0/51
]undo shutdown
]int f1/0/52
]undo shutdown
]irf-port-configuration active
]irf auto-update enable
 

Switch B

>system - view
] irf member 1 renumber 2
] quit 
> reboot
>system - view
]int f2/0/51 
]shutdown
]int f2/0/52
]shutdown
]irf-port 2/1
]port group interface FortyGigE2/0/51
]port group interface FortyGigE2/0/52
]int f2/0/51
]undo shutdown
]int f2/0/52
]undo shutdown
]irf-port-configuration active
]irf auto-update enable