C9300-24T#conf t
Enter configuration commands, one per line. End with CNTL/Z.
C9300-24T(config)#
C9300-24T(config)#boot system flash:packages.conf                              
C9300-24T(config)#
C9300-24T#show boot 
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Switch 1
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Current Boot Variables:
BOOT variable = flash:packages.conf;

Boot Variables on next reload:
BOOT variable = flash:packages.conf;
Manual Boot = no
Enable Break = no
Boot Mode = DEVICE
iPXE Timeout = 0