# Set up the capsule The firmware on a device is updated using a capsule, through the UEFI. This process involves capturing the firmware update payload in a capsule [.cap file], which is then processed by the system firmware to update the device firmware. Note The mentioned capsule update is applicable to Qualcomm Linux advanced and base variants only. ## Device firmware Updating device firmware involves installing new software onto a device’s firmware, which is the low-level software that controls the hardware. This process can improve the device’s performance, fix bugs, add new features, or enhance security. To configure the device firmware, see: [How to update device firmware using a capsule](https://docs.qualcomm.com/doc/80-70020-4/topic/How-tos.html#how-tos). ## **UEFI variables involved in capsule update** The communication between OS and UEFI is enabled using protocols and services that interact with the platform firmware. UEFI offers a standard boot environment, data tables with platform information, and boot/runtime service calls for the OS loader and OS. UEFI variables used in capsule update | Variable name | Description | | --- | --- | | OsIndications | This variable is owned by the OS and is used to indicate the features the OS wants the firmware to enable or the OS wants the firmware to take. This variable is set by OS and cleared by UEFI. | | OsIndicationsSupported | This variable is owned by the firmware and indicates which of the OS indication features and actions the firmware supports. | | OsTrialBootStatus - Is a 32 bit UEFI variable. | Bit map:



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> | | EFI system resource table (ESRT) | The ESRT table is set by the UEFI after the capsule update. | For more information about the OsIndications and OsIndicationsSupported variables, see [Exchanging information between the OS and Firmware](https://uefi.org/specs/UEFI/2.10/08_Services_Runtime_Services.html?highlight=osindications#exchanging-information-between-the-os-and-firmware). Note - If there is more than one capsule in the ESP partition (in EFI/UpdateCapsule), consider all the capsules for the update and update them alphabetically. - Store all UEFI non-volatile variables in the rollback protection memory block (RPMB) partition, which must be in a Provisioned state. > > > - Autoprovision the RPMB on Qualcomm secure-boot enabled devices. > - On Qualcomm non-secure devices, don’t autoprovision the RPMB; instead, provision it with test keys. > - If you provision the RPMB with test keys on non-secure devices, you can’t re-provision it with a device key when enabling Qualcomm secure boot on the device. > - Use the `rpmbClient` application for RPMB provisioning from Linux. For more information, see [Qualcomm Security Linux Guide](https://docs.qualcomm.com/bundle/publicresource/topics/80-70020-11/bring-up.html#verify-trustzone/device-configuration/hypervisor-image-loading). ## EFI system resource table for capsule update status > > > The ESRT is an optional mechanism to identify the device and the system firmware resources are used to provide firmware updates. Each ESRT entry describes a firmware resource that can be updated and reports the status of the last attempted update. > The entries in ESRT, which are used to report status of the last attempted update listed in the following table: Table: ESRT entries | **ESRT field** | **Description** | | --- | --- | | FwClass | The firmware class field contains a GUID that identifies a firmware component that can be updated through *UpdateCapsule().* | | FwType | Identifies the type of firmware resource. | | FwVersion | The firmware version field represents the current version of the firmware resource. The value must always increase as a larger number represents a newer version. | | LowestSupportedFwVersion | The lowest firmware resource version to which a firmware resource can be rolled back for the specified system/device. | | CapsuleFlags | The capsule flag field contains the *CapsuleGuid* flags (bits 0- 15) as defined in the *EFI\_CAPSULE\_HEADER* that’s set in the capsule header. | | LastAttemptVersion | The field describes the last firmware version for which an update was attempted (uses the same format as the firmware version). | | LastAttemptStatus | The field describes the result of the last firmware update attempt for the firmware resource entry. | The ESRT content is exposed by the OS from the sysfs path. /sys/firmware/efi/esrt/entries/entry0/ sh-5.1# cd /sys/firmware/efi/esrt/entries/entry0/ sh-5.1# ls capsule_flags fw_type last_attempt_status lowest_supported_fw_version w_class fw_version last_attempt_version Copy to clipboard The ESRT table is set by UEFI after the capsule update. X is the firmware version before the capsule update. Y is the version of the firmware, which is available in the capsule [.cap] file. Note Last attempted firmware version is available only if RPMB is provisioned. | **Last attempted firmware version** | **Current firmware version** | **last\_attempt satus** | **Capsule update scenario** | | --- | --- | --- | --- | | Y | Y | 0 | Update success | | Y | X | 1 | Capsule update failure | | 0 | X | 0 | Capsule meta-data failure | | Y | X | 0 | Firmware rollback done | For more information about ESRT, see [Firmware Update and Reporting - UEFI Specification 2.10 documentation](https://uefi.org/specs/UEFI/2.10/23_Firmware_Update_and_Reporting.html#efi-system-resource-table) The flowchart explains how the device firmware is updated using the UEFI capsule solution/method using different UEFI variables along with the rollback support. 1. **Initiation**: The over the air (OTA) update process starts, and the OS prepares to update the capsule, signaling the UEFI (through setting `OsIndications`) to begin the update. The OS sets a `TrialBootMaxCount` to track the number of trial boots allowed and then reboots the device. 2. **UEFI update**: Upon reboot, the system checks for `OsIndications`. If present, it performs the capsule update, updates the EFI system resource table (ESRT), clears `OsIndications`, and if `TrialBootMaxCount` is set, allows `TrialBootEnabled` and restarts the system again. 3. **Trialboot handling**: - If the `OsIndications` aren’t set, the system checks if the `TrialBootEnabled` is active. - If the `TrialBootEnabled` is active and the `TrialBootCount` equals the `TrialBootMaxCount`, it checks the rollback count. - If a rollback is allowed, the UEFI reverts to the firmware, updates the ESRT, and reboots. - If a rollback isn’t allowed, it indicates that the rollback limit is reached. - If the `TrialBootCount` is less than the `TrialBootMaxCount`, it increments the `TrialBootCount` and continues the process. 4. **Completion**: The system boots to the OS, checks the ESRT, and if the OS boots successfully, it resets the `TrialBootEnabled` field. 5. **Result**: - If `TrialBootEnabled` isn’t active, the OTA update is confirmed as complete. - The system clears the `OtaTrialBootStatus` and sets the `LwSupportedFwVersion` to the current firmware version to disable rollback. 6. **Recovery**: If a firmware capsule update fails during the update process, UEFI has a recovery mechanism to maintain the stability and functionality. > > > 1. **Rollback**: If a rollback is allowed, UEFI reverts to the previous firmware version. This involves restoring the firmware to the state before the update attempt. > 2. **ESRT update**: The ESRT is updated to reflect the rollback. > 3. **Reboot**: After the rollback is complete, the UEFI triggers a restart to ensure it’s running the previous, stable firmware version. This process ensures that the update is applied and allows for rollback if any issues are encountered during the trial period. ## Authentication and signing Authentication is essential for firmware updates to ensure security and stability. It guarantees that only updates from trusted sources are applied, preventing malicious or unauthorized updates. By verifying the digital signature of the capsule, it ensures the update hasn’t been tampered with during transmission and that only verified and tested updates are installed. This reduces the risk of system crashes or malfunctions due to faulty firmware. For more information, see : [How to authenticate and sign a capsule update](https://docs.qualcomm.com/doc/80-70020-4/topic/How-tos.html#how-tos). Last Published: Jun 25, 2025 [Previous Topic Update the device firmware](https://docs.qualcomm.com/bundle/publicresource/80-70020-4/topics/Update-the-device-firmware.md) [Next Topic Update capsule and trialboot rollback in base and advance variants](https://docs.qualcomm.com/bundle/publicresource/80-70020-4/topics/capsule-update-for-base-and-advance-variants.md)