Two 3750-24 x t before stack is made of a different version of the IOS:
The Switch Ports Model SW Version SW Image
-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30 WS - * 1 C3750X - 15.0 (2) 24 SE9 C3750E - UNIVERSALK9 -m
2 WS - 30 C3750X - 15.0 (2) 24 SE9 C3750E - UNIVERSALK9NPE -m

Show the boot:
The BOOT path - the list: flash:/c3750e - universalk9 - mz. 150-2. SE9. Bin
The Config file: flash:/Config. Text
Private Config file: flash:/Private - Config. Text
The Enable Break: no
Manual Boot: no
Allow Dev Key: yes
HELPER path - the list:
Auto upgrade: yes
Auto upgrade path:
NVRAM/Config file
Buffer size: 524288
The Timeout for the Config
Download: 0 seconds
The Config the Download
Via DHCP: disabled (next boot: disabled)
-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
The Switch 2
-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
The BOOT path - the list: flash:/c3750e - universalk9npe - mz. 150-2. SE9. Bin
The Config file: flash:/Config. Text
Private Config file: flash:/Private - Config. Text
The Enable Break: no
Manual Boot: no
Allow Dev Key: yes
HELPER path - the list:
Auto upgrade: no
Auto upgrade path:


Now I want to upgrade their IOS, the switch with the IOS 1, 2, each in IOS 2 start switch, but how to specify the boot command as if there is no mentioned switch2 with IOS 2 start, you have what way? Or I can only put the stacked line stired, separate start then connected to the stacked line?