how to check slot a b in fastboot A B - Fastbootset-activeslotcommand fastboot How to Check Slot A/B in Fastboot for Android Devices

Fastbootflashslot B Understanding your Android device's boot slots is crucial, especially when dealing with system updates, custom ROMs, or troubleshooting boot issuesHow does android bootloader know it has to boot from Slot Android's A/B partition scheme, also known as seamless updates, utilizes two sets of partitions, referred to as slots (typically Slot A and Slot B)2018721—checkthis article. Partitions on an Android device. A partition fastbootgetvar all | grep "current-slot"If you're on a Windows PC  This allows for updates to be installed in the background on one slot while the device boots from the other, minimizing downtimeA/B system updates ensures modern approach for system update. This feature allows one to use two sets (or more) of partitions referred to asslots. Knowing how to check slot a/b in fastboot is a fundamental skill for any advanced Android userThenfastbootflash boot_b Then the last 2 lines that turned it into brick wasfastboot--set-slot=b andfastbootreboot seethe storage device, it says 

The Fastboot mode is a powerful diagnostic and maintenance protocol that allows you to interact with your device's bootloaderA/B system updates ensures modern approach for system update. This feature allows one to use two sets (or more) of partitions referred to asslots. When it comes to checking which slot is currently active and which is available, Fastboot provides straightforward commands2025122—Regardless of what the currentslotis, there is oneslotthat is the activeslot(the one the bootloader will boot from on the next boot) or 

Verifying Your Current Boot Slot

To check your device's current active boot slot, you'll need to enter Fastboot mode-Do you install the recovery images to the boot partition? (broke phone), Do you need to do it TWICE? (install to boot, reboot, install to boot again to swapslots? why notfastbootboot install --slotall??) Do you just work from a TWRP fastloaded to memory but not installed and then install the  The method for entering Fastboot mode varies depending on the device manufacturer, but commonly involves powering off your device and then holding a specific button combination (often Volume Down + Power)20251016—One workaround that I found is that you'll have to first execute the desiredFastbootcommand and then connect your device to the PC via USB  Once in Fastboot mode, connect your device to your computer via USB-Do you install the recovery images to the boot partition? (broke phone), Do you need to do it TWICE? (install to boot, reboot, install to boot again to swapslots? why notfastbootboot install --slotall??) Do you just work from a TWRP fastloaded to memory but not installed and then install the 

The primary command to find out which slot your device is currently configured to boot from is:

```bash

fastboot getvar current-slot

```

When you execute this command in your terminal or command prompt, the output will clearly indicate either `current-slot: a` or `current-slot: b`A/B + twrp How do the slots actually work? r/LineageOS This tells you which of the two slots is presently designated as the active one4. set Bslotas active "fastboot-ab" and reboot. After aboving setting, the device should be able to boot from both A/B  For example, if the output is `current-slot: a`, your device is set to boot from Slot AA/B (seamless) system updates If it shows `current-slot: b`, then Slot B is the active boot slot2025122—Regardless of what the currentslotis, there is oneslotthat is the activeslot(the one the bootloader will boot from on the next boot) or 

It's important to understand that even though one slot is active, the other slot (inactive slot) can still be accessed4. set Bslotas active "fastboot-ab" and reboot. After aboving setting, the device should be able to boot from both A/B  This is fundamental to the A/B update processHow A/B Partitions and Seamless Updates Affect Custom While the active slot is used for booting, the inactive slot can be updated and prepared for the next boot cycle2018721—checkthis article. Partitions on an Android device. A partition fastbootgetvar all | grep "current-slot"If you're on a Windows PC 

Understanding Slot Functionality in A/B Systems

The A/B update mechanism is designed to ensure that system updates are applied without interrupting your current usageHow to automate slot selection after android AB-Update When an update is available, it is typically installed on the inactive slotA/B Boot Failure Partition B Fails to Boot But Partition A Works For instance, if Slot A is currently the active slot, the update will be applied to Slot BCheckhttps//play.google.com/store/apps/details What'sA BPartition Android System & Seamles System Updates, TWRPSlotASlotB ! Once the update is successfully installed and verified, the bootloader can be instructed to switch the active slot to the updated one, ready for the next rebootCheckhttps//play.google.com/store/apps/details What'sA BPartition Android System & Seamles System Updates, TWRPSlotASlotB ! This process is often referred to as seamless updatesHow to automate slot selection after android AB-Update

There are instances where you might need to manually switch between slotserror Failed to identify currentslot. Diffing the results offastbootgetvar all with SD card, compared to eMMC, Iseethe following differences. This can be done using the following command:

```bash

fastboot --set-slot=[a|b]

```

Or, to switch to the *other* slot:

```bash

fastboot set_active other

```

After executing `fastboot set_active other`, a subsequent `fastboot reboot` command will initiate the boot process from the slot that was previously inactive20251016—One workaround that I found is that you'll have to first execute the desiredFastbootcommand and then connect your device to the PC via USB  This is a common troubleshooting step if a device fails to boot correctly after an update via the active slot20251016—One workaround that I found is that you'll have to first execute the desiredFastbootcommand and then connect your device to the PC via USB 

Troubleshooting Common Fastboot Slot Issues

One common error users encounter is `fastboot: error: Failed to identify current slot`What is your boot slot? r/GooglePixel This can sometimes occur due to a temporary communication issue or if the device's bootloader is in a state where it cannot reliably determine the current slotA/B (seamless) system updates A workaround for this is to first execute the desired Fastboot command and then connect your device to the PC via USB, or to try rebooting the device into Fastboot again2018721—checkthis article. Partitions on an Android device. A partition fastbootgetvar all | grep "current-slot"If you're on a Windows PC 

If you encounter a scenario where one slot fails to boot but the other works, you can attempt to set the working slot as activeWhat is your boot slot? r/GooglePixel For example, if Partition B fails to boot but Partition A works, you would execute:

```bash

fastboot --set-slot=a

```

Followed by:

```bash

fastboot reboot

```

This command ensures that your device attempts to boot from Slot A on the next restartHow A/B Partitions and Seamless Updates Affect Custom

For more advanced users or custom ROM enthusiasts, commands like `fastboot flashall` or `fastboot flash boot_a` and `fastboot flash boot_b` are used to flash specific partitions to individual slotsSeamless System Updates | TWRP Slot A Slot B | Dot SM It's critical to understand which slot you are targeting before executing these commands, as flashing to the wrong slot can lead to boot issues2025815—Fix 1 Boot via InactiveSlot· To begin with, execute the below command to switch to anotherslotfastbootset_active other · Now reboot your 

In summary, mastering how to check slot a/b in fastboot is an essential skill for maintaining and customizing Android devices that utilize A/B partition schemes2025122—Regardless of what the currentslotis, there is oneslotthat is the activeslot(the one the bootloader will boot from on the next boot) or  By using commands like `fastboot getvar current-slot` and `fastboot set_active`, you gain greater control and understanding of your device's update and boot processes2025815—Fix 1 Boot via InactiveSlot· To begin with, execute the below command to switch to anotherslotfastbootset_active other · Now reboot your  Always ensure you know which slot you are interacting with to avoid unintended consequences20251016—One workaround that I found is that you'll have to first execute the desiredFastbootcommand and then connect your device to the PC via USB