Yeah, I have already thrown in a 2GB stick of DDR2 SODIMM RAM and upgraded to the latest version out there:
<HP>display version
HPE Comware Platform Software
Comware Software, Version 5.20.105, Release 1810P13
Copyright (c) 2010-2017 Hewlett Packard Enterprise Development LP
HPE 5820X-24XG-SFP+ TAA Switch uptime is 0 week, 0 day, 0 hour, 2 minutes
HPE 5820X-24XG-SFP+ TAA Switch with 2 Processors
1792M bytes SDRAM
4M bytes Nor Flash Memory
512M bytes Nand Flash Memory
Config Register points to Nand Flash
Hardware Version is Ver.C
CPLDA Version is 002, CPLDB Version is 004
BootRom Version is 303
[SubSlot 0] 24SFP Plus+4GE Hardware Version is Ver.C
Like you mentioned, it was very easy. I was worried about the BOOTROM as well because it originally had 220 and needed 303 to run the newest version. I found this article:
HPE Support document - HPE Support Center
So I just risked it and copied the newest version onto flash, set the boot-loader and rebooted. It upgraded the BootRom during the reboot process and ran through some other stuff and booted into the new version.
Now to get some SFP+ modules and start messing around with it!