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Carrier unlocked vs. bootloader unlocked: why some phones can't run a de-Googled OS

Checked against the makers' own pages · Last reviewed October 15, 2026

Two different locks

The carrier lock is the one meant when a phone is sold as "unlocked." The FCC describes it as software that keeps many US phones off other networks "even when those networks are technologically compatible." Verizon's own policy says "Unlocking" "refers specifically to disabling the software that prevents a device designed for one carrier from being activated on another."

The bootloader is the small program that starts the phone and loads the operating system. Android's documentation says "most Android devices ship with a locked bootloader, meaning that users can't flash the bootloader or device partitions." iodé, the maker of iodéOS, explains that unlocking it "removes manufacturer restrictions and allows users to flash custom firmware (such as ROMs, kernels, and recoveries)."

The LineageOS glossary puts the two side by side: carrier unlocking means "You can use the device with SIM cards of any carrier," while bootloader unlocking means "You can run unsigned operating systems/kernels," and that second kind "is the type of unlock you need to install a Custom ROM." CalyxOS adds: "unlocking bootloader is different from unlocking a carrier-locked phone." [1][2][3][4][5][7]

How carrier unlocking works

The FCC says that unless a phone "is specifically sold as "unlocked" at the point of purchase, it is probably locked to a specific wireless provider's network," whether you buy it from a carrier, a store or a third party. Google says a Pixel bought from a mobile service provider "could be SIM-locked for up to 2 years," and that "All phones in the Google Store come unlocked."

Each big carrier posts its rules (as of Oct. 15, 2026):

• Verizon: new phones are locked to Verizon. Postpaid phones unlock automatically when bought at full retail price or once the financing balance is paid; prepaid phones unlock after 365 days of paid and active service.
• AT&T: the phone was bought more than 60 days ago, is paid in full, isn't reported lost or stolen, and your account isn't past due; prepaid phones need 12 months of paid service.
• T-Mobile: postpaid phones active for at least 40 days and paid off; prepaid phones after 365 days, or sooner with more than $100 in refills.

None of these policies says anything about the bootloader. Carrier unlocking only removes the network lock, and the FCC adds that unlocking "may not make the phone technologically compatible with another wireless provider's network." Our phone bands guide covers that part. [3][4][8][9][10]

How bootloader unlocking works: the OEM unlocking switch

On Android phones that allow it, unlocking the bootloader takes two steps. First you turn on OEM unlocking in Settings > System > Developer options. Android's documentation says phones "should deny the fastboot flashing unlock command" until that option is on. Then you connect the phone to a computer and send the unlock command. Android's documentation says the phone should then warn you and do a factory data reset, which erases everything on it.

Every one of these systems starts here:

• GrapheneOS: its install guide says "OEM unlocking needs to be enabled from within the operating system," then has you "toggle on the OEM unlocking setting."
• CalyxOS: its guide walks you through Developer options to the OEM unlocking switch and says that if you can turn it on, "this phone allows bootloader unlocking and you can install CalyxOS."
• /e/OS: its documentation says "To flash a custom ROM like LineageOS or /e/OS you need to unlock the bootloader of your device," which needs you, as the owner, to grant permission through OEM unlocking.
• LineageOS: its install guides (for example the Pixel 9's) say "Enable OEM unlock in the Developer options under device Settings, if present," then unlock with fastboot. The /e/OS guide for the same phone uses the same wording.
• iodéOS: iodé's manual install instructions for Pixels start with "Unlock OEM in developer settings," then "fastboot flashing unlock." Its documentation says unlocking the bootloader "allows users to flash custom firmware."

GrapheneOS adds a detail that matters for carrier phones: "On device model variants (SKUs) which support being sold as locked devices by carriers, enabling OEM unlocking requires internet access so that the stock OS can check if the device was sold as locked by a carrier." [1][5][7][11][12][13][14][15]

Why phones sold by carriers can be stuck

GrapheneOS explains what happens inside a carrier Pixel: "Carrier variants of Pixels use the same stock OS and firmware with a non-zero carrier id flashed onto the persist partition in the factory. The carrier id activates carrier-specific configuration in the stock OS including disabling carrier and bootloader unlocking." GrapheneOS adds that "the hardware is the same."

Its FAQ says devices sold in partnership with carriers "may be locked by the carrier," that this "is primarily an issue with US carriers and isn't common elsewhere in the world," and that you should "either don't buy a carrier device, or make sure it can be unlocked." CalyxOS says "Google and most of the carriers allow you to enable OEM unlocking," with Verizon as the exception (next section).

Carriers aren't the only ones. The LineageOS glossary notes "Some OEMs don't allow unlocking the bootloader," and the /e/OS documentation says porting /e/OS to any device depends first on "Is it possible to unlock the bootloader." [1][2][11][16][17]

Verizon phones

CalyxOS's install page warns: "Pixel phones from mobile carrier Verizon in the United States are not able to install CalyxOS due to bootloader unlocking prohibitions, please ensure your device is not from Verizon if purchased secondhand." Its Verizon page says "The Verizon Pixels prohibit their users from unlocking bootloader, thus, you cannot install any custom Android OS on it." That covers GrapheneOS, /e/OS, LineageOS and iodéOS as much as CalyxOS, because all of them need the bootloader unlocked first.

Paying off a Verizon phone carrier-unlocks it, but Verizon's policy defines unlocking only as removing the network lock. As LineageOS puts it, some carriers remove the SIM lock "but still won't allow unlocking the bootloader."

GrapheneOS says a carrier "may be able to remotely disable" the bootloader block, "but their support staff may not be aware and they probably won't do it," and that "If you CAN figure out a way to unlock a carrier device, it isn't a problem." Its advice: "Get a carrier agnostic device to avoid the risk and potential hassle."

The sources above describe Verizon's Pixels. For other brands sold by Verizon, check the install guide for your exact model on the system's own site and test the OEM unlocking switch before you rely on it. [1][2][4][6][11][12][13][14][15]

How to check before you buy

1. Buy from the maker if you can. Google says every phone in the Google Store comes unlocked, and CalyxOS says Google allows OEM unlocking. GrapheneOS's advice is to "Get a carrier agnostic device."
2. Check that the system supports your exact model. /e/OS asks you to "Confirm your exact model in the Device Selector" and check that the model number matches yours exactly. Look up the phone on the GrapheneOS, CalyxOS, /e/OS, LineageOS or iodéOS page first.
3. Test the OEM unlocking switch. Tap Build number 7 times (Settings > About phone) to turn on Developer options, then open Developer options and find OEM unlocking. CalyxOS says that if you can turn it on, "this phone allows bootloader unlocking," and that "If "OEM unlocking" is greyed out, you may have the Verizon version." The switch may not work without internet; CalyxOS says to connect to Wi-Fi, remove the SIM card and try again. Turn it back off if you're not installing anything yet.
4. Be careful with used and refurbished phones. Verizon carrier-unlocks paid-off phones, but CalyxOS says Verizon Pixels still don't allow bootloader unlocking, so "unlocked" in a listing doesn't tell you whether the bootloader can be unlocked. The FCC says to "ask if the phone is locked or unlocked" when buying new or used, and CalyxOS says to make sure a secondhand Pixel is "not from Verizon." Ask the seller to test the OEM unlocking switch, or buy where you can return it.
5. Sign out of Google before you install. CalyxOS warns that if factory reset protection (FRP) is on when you flash and relock, "you will not be able to turn OEM unlocking back on." /e/OS likewise says to log out of any Google or other accounts before you start.

For buying a Pixel to run GrapheneOS, see how to buy a GrapheneOS phone. For the whole process, see how to de-Google an Android phone. [1][3][4][6][8][11][14]

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