I was going to go a different route on this, and ultimately I have a larger goal to this, but I am going to take a new fork in the road to solve the problem immediately, hopefully, and then go back and pick up the ultimate goal.
Some quick (I hope) Background:
I have some setups which need, or use HIGH BANDWIDTH USB connections (NOT disks!, and not relevant in the big picture honestly), so the best way to is to use USB PORTS with DEDICATED CONTROLLER PER PORT.
Sooooo... after some research and what others were using these StarTech cards were the solution...or were they
??
The big issue with these cards at the time I first found them, they were $120/EACH! Holy pricey Batman! Any way a year or so goes by and I get "lucky" and find some NEW IN BOX ones on the aucitons site.. MINE! $100 for TWO of them! WOOT! Happy Dance... don't look Ethel!

Any way fast forward to the new box to use one of these... Since I only use ESR's.. I put 20.04 on this new purpose built box... slap the card in! lscpi, lsusb shows the card... good to go! NOPE! wahaahhaa... Nothing works in the the ports! They show up.. but nothing works when plugged up...As I recall... I messed with making sure all updates were done, and it was done when I built it, I let the installer do it .... So I scratch my head... and find that this is a firmware issue. And that regardless what StarTech and others with similar clones of these cards say, they are NOT LINUX 2.10 or better compatible!
Well fast forward as certain other things intervened that this box as built is not going to work for other reasons in the setup needed. Its not got enough CPU to run this software... So.. it sort of was relegated to just sit there... and use for other purposes..
So one day I stick in the devices I need to the box to test things..and MAGICALLY NOW 3 of 4 ports WORK! No more messages in dmesg about firmware...
No idea what the issue is with the one, but it won't work,period. ( yes I am have plugged in the adidtional power via molex and SATA, same results) So I use it for testing purposes on things... and move along with plans for another better build and use the other card.....
Where we are TODAY:
So new box, with beef to run this software and these devices in their high bandwidth needs 16 cores and 32 threads! Rraraahaha more powerr! (Tim the Toolman Vocie!
)
So build it up, slap in that other card... and here we are! 24.04 used. Fully updated... and back to where we were about 1.1.5 years ago.
Rrrrhrotttroooo Rhagggy!
A quick check of lspci
lspci
03:00.0 USB controller: Renesas Technology Corp. uPD720202 USB 3.0 Host Controller (rev 02)
04:00.0 USB controller: Renesas Technology Corp. uPD720202 USB 3.0 Host Controller (rev 02)
05:00.0 USB controller: Renesas Technology Corp. uPD720202 USB 3.0 Host Controller (rev 02)
06:00.0 USB controller: Renesas Technology Corp. uPD720202 USB 3.0 Host Controller (rev 02)
Check!
lsmod | grep xhci_pci
xhci_pci 24576 0
xhci_pci_renesas 20480 1 xhci_pci
Check!
dmesg:
dmesg gives this:
xhci_hcd 0000:03:00.0: failed to load firmware renesas_usb_fw.mem, fallback to ROM
Same for all ports 3-6. Sighhhh....
I have no idea what magic incantation of the magical words scared the other box in to at least 3 ports working, and I really only need 2, and I call it a win... but.. sigh my use of the magical words right now is not scaring it enough this time.
I ran accross this in the past which has some sort of firmware stuff in it:
https://github.com/denisandroid/uPD72020x-Firmware
BUT it has an infection of winslobber stuff, and doesn't seem to have any purpose for Linux at all... BUT WAIT!
Digging around this go around I found out some stuff from Arch which points to this stuff, and appears to install firmware for Linux, Linuces? to use! Ok ... what is it doing

First off this WAY WAY ABOVE MY PAY GRADE now..
Here:
https://aur.archlinux.org/packages/upd72020x-fw
Hmmm..
Ok... wooohoo... Hmmm.. What do I do with this in Kubuntu or any other Linux for that matter... I don't have a clue!
So what does this unicorn package do??
OK.. BINGO! Those update.mem files in the other gitbhub is the firmware! ! !
So maybe some how the other/first box magically got this file
Nope... Can't find that renesas_usb_fw.mem on there... Can't find that on the new box... sigh...
Ok.. lets look in /urs/lib/firmware.. that don't exist in *buntu/Debian

Ok.. *buntu/Debian land in /lib/firmware
Ok.. tons of files and directories (that I have no clue what do
) any way.. NO mem files in there! Lots of zst files ... search of what these are.. oh... compressed firmware is an option now... ok... what ever.. yeah... you'd be correct if I see little value in that.. but I don't care so long as it works for stuff...
Which leads to the POINT/TL ; DR of this:
If pull this update.mem file in, rename it to renesas_usb_fw.mem
Then what??
What directory
just into /lib/firmware? Needs its own directory reneasas and the dump it in there?? Make some zst file? How
I guess this is some sort of compressor program that can be installed
? Again, I am in WAY OVER MY HEAD ON THIS.. I don't normally dig this deep into the guts of Linux...
Do I need to something that mimics this install command from Arch.. seems that I found something that points that this "install -Dm644" is equal to something in initram tools to get Kubuntu to use this, find it etc... I can't seem to find my note on this right this second.....oh... hold up Batman! Found it! mkinitcpio-firmware
Is that it
? Being out of my zone.. I am not sure on this...so... take it to be a wild guess on this! 
So this is where I am hoping that some of the gurus here can point to what do to with this file and get Kubuntu 24.04 and 20.04 to find it, use it for the card...
I am sure that sticking that update renamed as something else is not all that it takes... and no I didn't try that.. as one I don't know where to put it as per above, and right now I am letting this box "bake" as it were for testing purposes.
So any of you firmware gurus know where to stick this? Magic command or "words"
to get the kernel to use it
I have hammers available too! 
New box:
6.11.0-19-generic #19~24.04.1-Ubuntu SMP PREEMPT_DYNAMIC Mon Feb 17 11:51:52 UTC 2 x86_64 x86_64 x86_64 GNU/Linux
YES I am also looking at alternate cards which do not use this controller which I've found out has issues in Linux... which earlier research appeared to solve it.. .but no.
I'd still like to resolve this for myself, and others with these cards. StarTech and even SIIG are using the SAME CARD from who ever in Asia OEM's it..
Thanks in advance!
Some quick (I hope) Background:
I have some setups which need, or use HIGH BANDWIDTH USB connections (NOT disks!, and not relevant in the big picture honestly), so the best way to is to use USB PORTS with DEDICATED CONTROLLER PER PORT.
Sooooo... after some research and what others were using these StarTech cards were the solution...or were they

The big issue with these cards at the time I first found them, they were $120/EACH! Holy pricey Batman! Any way a year or so goes by and I get "lucky" and find some NEW IN BOX ones on the aucitons site.. MINE! $100 for TWO of them! WOOT! Happy Dance... don't look Ethel!


Any way fast forward to the new box to use one of these... Since I only use ESR's.. I put 20.04 on this new purpose built box... slap the card in! lscpi, lsusb shows the card... good to go! NOPE! wahaahhaa... Nothing works in the the ports! They show up.. but nothing works when plugged up...As I recall... I messed with making sure all updates were done, and it was done when I built it, I let the installer do it .... So I scratch my head... and find that this is a firmware issue. And that regardless what StarTech and others with similar clones of these cards say, they are NOT LINUX 2.10 or better compatible!
Well fast forward as certain other things intervened that this box as built is not going to work for other reasons in the setup needed. Its not got enough CPU to run this software... So.. it sort of was relegated to just sit there... and use for other purposes..
So one day I stick in the devices I need to the box to test things..and MAGICALLY NOW 3 of 4 ports WORK! No more messages in dmesg about firmware...




Where we are TODAY:
So new box, with beef to run this software and these devices in their high bandwidth needs 16 cores and 32 threads! Rraraahaha more powerr! (Tim the Toolman Vocie!

So build it up, slap in that other card... and here we are! 24.04 used. Fully updated... and back to where we were about 1.1.5 years ago.
Rrrrhrotttroooo Rhagggy!
A quick check of lspci
lspci
03:00.0 USB controller: Renesas Technology Corp. uPD720202 USB 3.0 Host Controller (rev 02)
04:00.0 USB controller: Renesas Technology Corp. uPD720202 USB 3.0 Host Controller (rev 02)
05:00.0 USB controller: Renesas Technology Corp. uPD720202 USB 3.0 Host Controller (rev 02)
06:00.0 USB controller: Renesas Technology Corp. uPD720202 USB 3.0 Host Controller (rev 02)
Check!
lsmod | grep xhci_pci
xhci_pci 24576 0
xhci_pci_renesas 20480 1 xhci_pci
Check!
dmesg:
dmesg gives this:
xhci_hcd 0000:03:00.0: failed to load firmware renesas_usb_fw.mem, fallback to ROM
Same for all ports 3-6. Sighhhh....
I have no idea what magic incantation of the magical words scared the other box in to at least 3 ports working, and I really only need 2, and I call it a win... but.. sigh my use of the magical words right now is not scaring it enough this time.
I ran accross this in the past which has some sort of firmware stuff in it:
https://github.com/denisandroid/uPD72020x-Firmware
BUT it has an infection of winslobber stuff, and doesn't seem to have any purpose for Linux at all... BUT WAIT!
Digging around this go around I found out some stuff from Arch which points to this stuff, and appears to install firmware for Linux, Linuces? to use! Ok ... what is it doing


First off this WAY WAY ABOVE MY PAY GRADE now..
Here:
https://aur.archlinux.org/packages/upd72020x-fw
Hmmm..
Renesas uPD720201 / uPD720202 USB 3.0 chipsets firmware |
Ok... wooohoo... Hmmm.. What do I do with this in Kubuntu or any other Linux for that matter... I don't have a clue!
So what does this unicorn package do??
Code:
# Maintainer: Jack Chen <redchenjs@live.com> pkgname=upd72020x-fw pkgver=1.0.0 pkgrel=2 epoch=1 pkgdesc="Renesas uPD720201 / uPD720202 USB 3.0 chipsets firmware" arch=('any') url="https://github.com/denisandroid/uPD72020x-Firmware" license=('custom') source=( "uPD72020x-Firmware-$pkgver.tar.gz::https://codeload.github.com/denisandroid/uPD72020x-Firmware/tar.gz/refs/tags/$pkgver" "remove.hook" ) sha512sums=( '9d7e61c99a0f46d0ae96505317e763a468d3e8006f7398d10 899ab78532b1ace608662b8a1b410a5577b268dc1f9275d1eb e3d03d209b85b2c4307ceb48dd261' '47aa4c4c3a0014df79b7a7998edfbc7b436ae6e966432f378 7d9f1655c986591c73165de6fad52ebb5cefd4f8101b9b094d 117f0508cd1f8f0d2c7396bbd3f91' ) package() { install -Dm644 "uPD72020x-Firmware-$pkgver/UPDATE.mem" "$pkgdir/usr/lib/firmware/renesas_usb_fw.mem" install -Dm644 "uPD72020x-Firmware-$pkgver/License.rtf" "$pkgdir/usr/share/licenses/$pkgname/LICENSE.rtf" # firmware install & remove hooks install -Dm644 /dev/null "$pkgdir/usr/lib/initcpio/hooks/$pkgname" install -Dm644 remove.hook "$pkgdir/usr/share/libalpm/hooks/$pkgname.hook" }
So maybe some how the other/first box magically got this file

Ok.. lets look in /urs/lib/firmware.. that don't exist in *buntu/Debian


Ok.. *buntu/Debian land in /lib/firmware
Ok.. tons of files and directories (that I have no clue what do

Which leads to the POINT/TL ; DR of this:
If pull this update.mem file in, rename it to renesas_usb_fw.mem
Then what??
What directory



Do I need to something that mimics this install command from Arch.. seems that I found something that points that this "install -Dm644" is equal to something in initram tools to get Kubuntu to use this, find it etc... I can't seem to find my note on this right this second.....oh... hold up Batman! Found it! mkinitcpio-firmware




So this is where I am hoping that some of the gurus here can point to what do to with this file and get Kubuntu 24.04 and 20.04 to find it, use it for the card...
I am sure that sticking that update renamed as something else is not all that it takes... and no I didn't try that.. as one I don't know where to put it as per above, and right now I am letting this box "bake" as it were for testing purposes.
So any of you firmware gurus know where to stick this? Magic command or "words"




New box:
6.11.0-19-generic #19~24.04.1-Ubuntu SMP PREEMPT_DYNAMIC Mon Feb 17 11:51:52 UTC 2 x86_64 x86_64 x86_64 GNU/Linux
YES I am also looking at alternate cards which do not use this controller which I've found out has issues in Linux... which earlier research appeared to solve it.. .but no.
I'd still like to resolve this for myself, and others with these cards. StarTech and even SIIG are using the SAME CARD from who ever in Asia OEM's it..
Thanks in advance!