I have been dealing with Brocade for years way back before the ICX... They used to have FastIron FWS such as the 648G.
At any rate, it is pretty good stuff all around. I am not certain which document you read, but for upgrading you do not need to erase the flash. This automatically happens when the upgrade process goes to write the image. I found a random ICX6450-C12-PD lying not far from my desk, so I will do one to make an example...
You should also validate the image, too. This is how I do it:
show flash
verify md5 primary
verify md5 secondary
^ There is a file with the MD5 checksums for the images packaged with your firmware to compare against.
************************
ICX6450-C12PD Router#sh flash
Stack unit 1:
Compressed Pri Code size = 9806840, Version:08.0.30hT313 (ICX64R08030h.bin)
Compressed Sec Code size = 9806840, Version:08.0.30hT313 (ICX64R08030h.bin)
Compressed Boot-Monitor Image size = 786944, Version:10.1.05T310
Code Flash Free Space = 32563200
ICX6450-C12PD Router#copy tftp flash 10.1.2.3 ICX64S08030s.bin primary
ICX6450-C12PD Router#Load to buffer (8192 bytes per dot)
.........................................................................................................................................................................................................................................................................................................................................................................................
SYNCING IMAGE TO FLASH. DO NOT SWITCH OVER OR POWER DOWN THE UNIT(8192 bytes per dot)...
....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
TFTP to Flash Done.
ICX6450-C12PD Router#sh fl
Stack unit 1:
Compressed Pri Code size = 8558924, Version:08.0.30sT311 (ICX64S08030s.bin)
Compressed Sec Code size = 9806840, Version:08.0.30hT313 (ICX64R08030h.bin)
Compressed Boot-Monitor Image size = 786944, Version:10.1.05T310
Code Flash Free Space = 32559104
ICX6450-C12PD Router#verify md5 pri
ICX6450-C12PD Router#..................................................................................................................................Done
Size = 8558924, MD5 bf544836ea83c4e6539f86a9fb497a4e
ICX6450-C12PD Router#reload
Are you sure? (enter 'y' or 'n'): y
Could not verify if the Running Config data has been changed.
Do you want to continue the reload anyway? (enter 'y' or 'n'):
The system is g
Sent SIGTERM to all processes
Sent SIGKILL to all processes
Requesting system reboot
Restarting system.
Bootloader Version: 10.1.05T310 (Mar 19 2015 - 16:39:59)
Model ID: 1.0.0.0.1.1
Enter 'b' to stop at boot monitor: 1 0
bootdelay: ===
Booting image from Primary
## Booting image at 00007fc0 ...
Created: 2018-05-30 14:30:33 UTC
Data Size: 8558348 Bytes = 8.2 MB
Load Address: 00008000
Entry Point: 00008000
Verifying Checksum ... OK
OK
Starting kernel in BE mode ...
Uncompressing Image...................................................................................................................................................................................................................................................................................................................................................................... done, booting the kernel.
IP-Config: Gateway not on directly connected network.
Config partition mounted.
Creating TUN device
Starting the FastIron.
FIPS Disabled:PORT NOT DISABLED
platform type 49
OS>Unable to set the kernel wall time
Starting Main Task .INFO: startup config data is not available, try to read from backup
INFO: startup config data in the backup area is not available
CPSS DxCh Version: cpss3.4p1 release
Pre Parsing Config Data ...
INFO: empty config data in the primary area, try to read from backup
INFO: empty config data in the backup area also
Parsing Config Data ...
INFO: empty config data in the primary area, try to read from backup
INFO: empty config data in the backup area also
System initialization completed...console going online.
Copyright (c) 1996-2016 Brocade Communications Systems, Inc. All rights reserved.
UNIT 1: compiled on May 30 2018 at 07:29:29 labeled as ICX64S08030s
(8558924 bytes) from Primary ICX64S08030s.bin
SW: Version 08.0.30sT311
Boot-Monitor Image size = 786944, Version:10.1.05T310 (kxz10105)
HW: Stackable ICX6450-C12-PD
==========================================================================
UNIT 1: SL 1: ICX6450C 12-port-PD Management Module
Serial #: XXX1234A01X
License: BASE_SOFT_PACKAGE (LID: eviHKKFmFMi)
P-ENGINE 0: type DEF0, rev 01
==========================================================================
UNIT 1: SL 2: ICX6450C-Copper 2port 2G Module
==========================================================================
UNIT 1: SL 3: ICX6450C-Fiber 2port 2G Module
==========================================================================
800 MHz ARM processor ARMv5TE, 400 MHz bus
65536 KB flash memory
512 MB DRAM
STACKID 1 system uptime is 6 second(s)
The system : started=warm start reloaded=by "reload"
ICX6450-C12PD Switch>
Stack unit 1 PS 1, Internal Power supply detected and up.
Stack unit 1 PS 1, Internal Power supply detected and up.
PoE: Stack unit 1 PS 1, Internal Power supply with 68000 mwatts capacity is up
PoE Info: Adding new 54V capacity of 68000 mW, total capacity is 68000, total free capacity is 68000
Stack unit 1 PS 2, One AT Mode detected and up.
Stack unit 1 PS 2, One AT Mode detected and up.
PoE: Stack unit 1 PS 2, One AT Mode with 0 mwatts capacity is up
PoE Info: Adding new 54V capacity of 0 mW, total capacity is 68000, total free capacity is 68000
PoE Info: PoE module 1 of Unit 1 on ports 1/1/1 to 1/1/4 detected. Initializing....
PoE Event Trace Log Buffer for 2000 log entries allocated
PoE Event Trace Logging enabled...
PoE Info: PoE module 1 of Unit 1 initialization is done.
ICX6450-C12PD Switch>