UPDATE: I just watched my video again and realized that my initial memory was faulty - I've updated the post to reflect that.
Hello Tony,
can you tell me how you updated your 54845A? Which files did you have to use and in which order? Maybe you can document the update process?
Thank you! 
Happy to.
As I mentioned above, I grabbed the MicroSolutions Backpack Parallel Port CDROM as this is what was recommended by Agilent in the doc "InfiniiumUpgradeRecovery.pdf".
To upgrade your non-LS-120 scope to A.04.xx, you will need the A.04.xx upgrade software on CD and the appropriate boot disk on a 3.5” floppy. You may contact Agilent technical support for copies of these disks, or download the files at the locations given below. The boot disk supports the MicroSolutions model 167550 Backpack CD-ROM drive. You may need to modify the files for compatibility with your drive.
There is a floppy disk image that I created - It is called "Bootimage.ima" - I used WinImage to write that to a 3.5" floppy and then I could boot the device with the Backpack installed and access the upgrade image. I would expect that you could use an IDE CDROM drive instead of the Backpack, you'll just have to have the right drivers in config.sys & autoexec.bat on the boot disk. Other than those files it is just a standard Win98 boot floppy.
To get to A.04.50, you need to start with A.04.30 and then upgrade that with the A.04.50 files.
The files you need to start with are in the "54845A\54845A\548xx\Upg_Rec\4_3\4_3_Recovery" folder. The files in those folders need to be burnt to CD, you can just use the standard Windows method to burn them as they aren't bootable. I put all the files from Disk 1-3 onto the one CD I think.
Once you have them in the drive you run Ghost.exe from the CD and select the HP548RCV.GHO" file. Ghost (
this is just a drive imaging tool) will push the new bits onto the disk and you should be at A.04.30.
I actually have a video of what I did to do the reinstall/upgrade on YT:
https://youtu.be/L49qug1oGuo?si=sh1auQQ3c-b901NC&t=536Now to get to A.04.50 I used the CDROMUPG.EXE utility - This is in the ZIP folder "54845A\54845A\548xx\Upg_Rec\bootdisk\CD_Boot.zip".
I really don't remember what files it looked for but I would start with the ones in "54845A\54845A\548xx\Upg_Rec\4_5\4_5_upg.zip". These have unique filenames so you should just be able to get them onto the same CD you used for A.04.30. Boot from the floppy again, run CDROMUPG.EXE and then follow the prompts.
I covered that in this video:
https://youtu.be/x9FUXcWENoU?si=lNKwF6aCO14yqmsr&t=142This is all from rewatching my videos and memory so my apologies if I've missed a step but it should be fairly straight forward.
Hope this helps.
TonyG