By the way, with some not so ancient devices you can search for the firmware here: https://software.cisco.com/download/home and at least get MD5 and SHA-512 hashes to verify the files you downloaded.

Not the case with this AP though.

Edit: Oh, I almost forgot. Also the exact filename. Makes it easy finding it online.

If you surprised why it has a PowerPC CPU. It's actually a SoC.
From the manual:

AMCC PowerPC 405 32-bit RISC processor core operating up to 333MHz with 16KB D-and I-caches.

Designed specifically to address embedded applications, the PowerPC 405EP (PPC405EP), provides a high-performance, low-power solution that interfaces to a wide range of peripherals by incorporating on-chip power management features and lower power dissipation requirements.

hard to say for sure, but U109 and U208 could be UART into those Cisco baseband or radio chips. one placement for the 2.4 GHz (G) and 5 GHz (A), respectively. would be interesting to probe around there and see if you get a serial interface to it... obviously for extra credit ;-)

Why something that old? WiFi standards move on and so does security.

However, if it isn't Broadcom you probably can get OpenWRT running