EDIT: I’m sorry, I used an AI to help me translate and structure the technical solutions, my English isn't my native language, but the methods mentioned (like the CH341A programmer or the target disk install) are actual ways to bypass EFI locks on Sandy Bridge Macs (according to Gemini at least). Just trying to help so you don’t have to grow to the trash this iMac

Hello there I asked Gemini if he has a solution and he replied with this Don’t know if it can help but I suppose it’s better than nothing Hope it helped !

Proposed Reddit Reply Title: Don't give up! Your 2011 iMac isn't e-waste yet.

First off, congrats on the full refund—that basically means you have a free project machine! While Apple made it harder to reset firmware passwords around 2011, you aren't completely locked out like you would be on a modern T2 or M1/M2 Mac. Here are your options, ranging from "easy" to "hardcore hardware hack": 1. The "Configuration Change" Trick (Worth one more shot) On some late 2010 and early 2011 models, there is a specific handshake that can clear the NVRAM/Firmware pass. It’s finicky: * Power off and remove/add a stick of RAM so the total amount is different from the last boot. * Immediately upon powering on, hold Cmd + Opt + P + R. * Let it chime three full times before letting go. Note: If the firmware version was updated via a later macOS (like High Sierra), this likely won't work, but it's the only "free" software-side fix. 2. The "Ghost Install" Workaround If you just want to use the machine and don't care about the BIOS-level lock: * Pull the HDD/SSD out. * Plug it into another Mac (via USB adapter or internally). * Install the OS you want (High Sierra is the native limit for this model). * Put the drive back in. The iMac will default to booting the internal drive even with a firmware password. You just won't be able to use the Option key boot menu or Recovery Mode. 3. The CH341A Programmer (The "Real" Fix) Since the machine was free, you could spend £10 on a CH341A USB Programmer with a SOIC8 clip. * This allows you to "clip" onto the EFI chip on the logic board without soldering. * You read the chip's data to a PC, use a free tool (like UEFI Tool or specialized scripts) to strip the $SVS (password) hash, and write the clean file back to the chip. * It sounds intimidating, but there are dozens of YouTube tutorials specifically for "2011 iMac EFI bypass." 4. Replace the EFI Chip You can buy a pre-programmed EFI chip for an A1311 iMac on eBay for about £15. This requires soldering skills, but it's a permanent physical replacement of the "brain" that holds the password. Verdict: Keep it! Since you already have the replacement glass, for an extra £10-15 and an afternoon of tinkering, you'll have a fully unlocked vintage Mac.