能否修改MBP启动时Touch Bar界面，启动前显示自定义JPG？

Great question—let’s break this down, since the Touch Bar’s behavior during boot and the pre-login phase is pretty tightly locked down by macOS’s firmware and security guardrails.

Can you fill the Touch Bar’s boot screen? #

Short answer: No, not with official or supported methods. The Touch Bar during boot is controlled directly by your Mac’s firmware (EFI/UEFI), which only displays system-defined elements like the boot progress bar, startup disk selection icons, or security prompts (like FileVault unlock). Apple doesn’t expose any APIs or settings to let you "fill" this screen with custom content—this is intentional to keep the boot process secure and consistent across devices.

While there are niche, unsupported hacks (like modifying firmware or disabling System Integrity Protection, SIP) that claim to tweak boot-stage behavior, these carry massive risks: you could brick your Mac, void your warranty, or expose your system to security vulnerabilities. Definitely not worth it for this use case.

Can you display a JPG on the Touch Bar before login/boot completion? #

Again, no official way to do this. The pre-login phase (after boot completes but before you enter your password) still has the Touch Bar controlled by the system’s login window process, which doesn’t support custom image display here.

Third-party tools that let you customize the Touch Bar (like BetterTouchTool) only work once you’re logged into your user account—they can’t interact with the pre-login environment. Even if you tried to modify system files related to the login window, SIP would block those changes by default. Disabling SIP might open the door to some experimental tweaks, but again, this undermines your Mac’s security and isn’t recommended for regular use.

Key Takeaway #

The Touch Bar’s boot and pre-login behavior is intentionally restricted by Apple to maintain system stability and security. All supported customization options are limited to when you’re logged into your user account.

内容的提问来源于stack exchange，提问作者Ricco Lesmana