[URGENT] Adding Flash plug-in to Chromium on RPi4 Ubuntu 19.10 (aarch64) + MATE

(Posting this because the last queries date back to 2018 and appear open)

As the subject line says, I urgently need to incorporate Adobe Flash support on the Pi 4 that I've built for my partner. It is running the 64-bit build of Ubuntu 19.10 (and the MATE desktop, in case it matters).

She is an educator and able to carry out all of her professional responsibilities, as well as all but one of her teach-from-home ones. That lone holdout is an old, district-designated web site from which she is required source material for her K-2 Special Education students. Unfortunately, that site uses Adobe Flash objects for everything. That's not an issue under normal circumstances because she has a Windows-based desktop in her classroom; she cannot get to it due to COVID-19 based closures and restrictions. Furthermore, this specific resource is being dropped outright at the end of this academic year, when it will be replaced by one of several that are under consideration and won't be named until then.

Anyway...

I have spent the better part of a week trying to add Adobe Flash support to Chromium to no avail. Although Adobe does offer a Flash plug-in (last updated 20.01.22, as of this writing), it is only built for 32 and 64-bit i386 processors. Since the Pi uses an ARM processor, that obviously won't work! There is a plug-in called PepperFlash, but that project appears completely abandoned. Another plug-in, gnash was last updated in 2012 and therefore seems abandoned as well. As for Adobe? They're discontinuing Flash at the end of 2020 (not that it matters), and they never supported ARM in the first place.

Needless to say, I've tried repeatedly to install PepperFlash and GNASH by following directions on a number of web sites. Likewise, I've followed far too many additional guides for adding Flash support to Chromium. Not one of those has worked. And all those attempts have come at a very great cost, including (on one occasion) wiping the SD card and starting from scratch.

At this point I am all out of ideas for how to get this running. It is imperative that the matter be resolved very soon, as her Pi is the only way she'll be able to meet her work obligations without preventing me from meeting my own.

I need help desperately!

Thank you in advance

Puffin browser includes, as far as I know, latest flash plugin. See this on PI4.
Hope it helps you.

The school district requires Chromium.

Her disability requires MATE.

Flash support is required for the balance of the 2019-2020 academic year.

There are no workarounds or substitutions.

Oh. Googling shows it seems a not very stable chromium flash plugin in Ubuntu. Another hypothetical remotely "workaround" trying help: not possible use Chromium normally and then get in puffin cloud browser? Permissions problem? Sorry if nosense.

The district is the one that requires the use of Chrome (and therefore Chromium). And for what remains of the academic year, they require that one particular site. Ironically, they're dropping that site with next year's curriculum. If the pandemic had taken place then, or the drop taken effect this academic year, we wouldn't be having this conversation.

The site in question uses flash to navigate and to retrieve curriculum materials. I'm not sure of the mechanics, but we did try to fetch materials in separate browsers, and also at separate times, on the only machine I have here that has Flash support; it did not work.

Because there are only so many hours in the day, because of deadlines within those hours, and because that machine was issued by my employer, it isn't an option for anything other than a control.

Finally: I understand that Raspbian has a stable, working flash plug-in built into its Chromium package. Unfortunately, when I first set my partner up with a Pi, she couldn't use that distribution; there's something about it that affects her disability. Ubuntu does not present the same problem, which is why I haven't taken the easy way out... LOL