2015 MBA stuck at base clock

[YoitsTmac]

We just got my friend a new M1 MBA. She said her 2015 was abysmally slow and wouldn't work unless it was plugged in. I took it because I like old tech. I'd love to add it to my home lab but it has a big issue I can't fix: it's stuck at the base clock of 900Mhz. Here's what I've done:

• remove the battery. I thought it was dead per my friend's information. After I dug deeper, it seems that was short sighting
• Run diagnostic, no issue (aside from missing battery)
• Verify fan spins, it does
• Reset NVRAM
• Reset SMC (not sure if this can be done without the battery? But I did)
• Install Intel power gadget, which is when I saw the CPU is locked at 900Mhz.

Any help would be appreciated!

 

[YoitsTmac]

bump? anyone? Has anyone heard of this behavior? I've been using Mac's for nearly two decades and fairly good with hardware troubleshooting, but this one has me baffled. I don't believe this one is dead.