root@EX3300> show chassis hardware
Hardware inventory:
Item             Version  Part number  Serial number     Description
Chassis                                xxx		 EX3300-48P
Routing Engine 0 REV 20   750-034250   xxx		 EX3300 48-Port POE+
FPC 0            REV 20   750-034250   xxx 		 EX3300 48-Port POE+
  CPU                     BUILTIN      BUILTIN           FPC CPU
  PIC 0                   BUILTIN      BUILTIN           48x 10/100/1000 Base-T
  PIC 1          REV 20   750-034250   xxx		 4x GE/XE SFP+
Power Supply 0                                           PS 900W AC
Fan Tray                                                 Fan Tray
{master:0}


root@EX3300> show system storage partitions
fpc0:
--------------------------------------------------------------------------
Boot Media: internal (da0)
Active Partition: da0s2a
Backup Partition: da0s1a
Currently booted from: backup (da0s1a)               <---------- HERE YOU CAN SEE WE ARE BOOTING OF BACKUP PARTITION

Partitions information:
  Partition  Size   Mountpoint
  s1a        183M   /
  s2a        184M   altroot
  s3d        369M   /var/tmp
  s3e        123M   /var
  s4d        62M    /config
{master:0}


root@EX3300> show system snapshot media internal
fpc0:
--------------------------------------------------------------------------
Information for snapshot on       internal (/dev/da0s1a) (backup)
Creation date: Apr 24 18:45:06 2019
JUNOS version on snapshot:
  jbase  : ex-12.3R12.4
  jkernel-ex-3300: 12.3R12.4
  jcrypto-ex: 12.3R12.4
  jdocs-ex: 12.3R12.4
  jswitch-ex: 12.3R12.4
  jpfe-ex33x: 12.3R12.4
  jroute-ex: 12.3R12.4
  jweb-ex: 12.3R12.4
  fips-mode-arm: 12.3R12.4
Information for snapshot on       internal (/dev/da0s2a) (primary)               <---------- HERE YOU CAN SEE I HAVE ALREADY MADE AN ATTEMPT TO COPY THE BACKUP PARTITION TO THE PRIMARY PARTITION ON JUNE 1 SO THE 2 PARTITIONS ARE THE SAME
Creation date: Jun 1 06:47:06 2021
JUNOS version on snapshot:
  jbase  : ex-12.3R12.4
  jkernel-ex-3300: 12.3R12.4
  jcrypto-ex: 12.3R12.4
  jdocs-ex: 12.3R12.4
  jswitch-ex: 12.3R12.4
  jpfe-ex33x: 12.3R12.4
  jroute-ex: 12.3R12.4
  jweb-ex: 12.3R12.4
  fips-mode-arm: 12.3R12.4
{master:0}


root@EX3300> show system alarms             <---------- HERE YOU CAN SEE THERE ARE NO ALARMS
No alarms currently active
{master:0}


root@EX3300> request system snapshot media internal slice alternate      <---------- I HAVE DONE THIS ABOUT 4 TIMES SO FAR
fpc0:
--------------------------------------------------------------------------
Formatting alternate root (/dev/da0s2a)...
Copying '/dev/da0s1a' to '/dev/da0s2a' .. (this may take a few minutes)
The following filesystems were archived: /
{master:0}


root@EX3300> request system reboot media internal slice alternate       <---------- THEN I REBOOT WITH COMMAND TO USE ALTERNATE PARTITION. 
Reboot the system ? [yes,no] (no) yes

Shutdown at Tue Jun  1 07:14:30 2021.
[pid 1966]

*** System shutdown message from root@EX3300 ***

System going down in 1 minute




*********** after reboot - check which partition is booting **********

root@EX3300> show system storage partitions
fpc0:
--------------------------------------------------------------------------
Boot Media: internal (da0)
Active Partition: da0s2a
Backup Partition: da0s1a
Currently booted from: backup (da0s1a)                 <---------- BUT IT STILL ONLY USES THE BACKUP PARTITION

Partitions information:
  Partition  Size   Mountpoint
  s1a        183M   /
  s2a        184M   altroot
  s3d        369M   /var/tmp
  s3e        123M   /var
  s4d        62M    /config
{master:0}


************* still booting off backup, tried this several times, will not boot off primary partition ************