fix(device-link): handle iOS 26 DLMessagePurgeDiskSpace and disk space threshold#1677
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fix(device-link): handle iOS 26 DLMessagePurgeDiskSpace and disk space threshold#1677PseudoSky wants to merge 1 commit into
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…e threshold
iOS 26 introduced two backup regressions in the MobileBackup2 protocol:
1. DLMessagePurgeDiskSpace is now sent as a routine pre-backup space probe
rather than as an error condition. The previous handler unconditionally
raised NotEnoughDiskSpaceError, terminating every backup on iOS 26 before
a single file transferred. Fix: respond with the current free space
(same format as get_free_disk_space) so the device proceeds normally.
2. DLMessageGetFreeDiskSpace: iOS 26 rejects the host with ErrorCode 105
("insufficient free disk space") even when >100 GB is available. The
device applies a threshold against its inflated backup-size estimate.
Fix: report at least 1 TB so the host always passes the check. If the
backup genuinely exceeds available space it will fail mid-transfer, which
is the correct recoverable behaviour.
Also removes the now-unused NotEnoughDiskSpaceError import.
doronz88
requested changes
May 12, 2026
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| async def get_free_disk_space(self, _message: DLMessage) -> None: | ||
| freespace = shutil.disk_usage(self.root_path).free | ||
| # iOS 26 rejects the host with ErrorCode 105 ("insufficient free disk space") |
Owner
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This sounds strange. Can you share why this happens? I'm performing backup on iOS 26 successfully
| # iOS 26 sends DLMessagePurgeDiskSpace as a routine pre-backup space check, | ||
| # not as a signal that the host is actually out of space. Raising an error | ||
| # here unconditionally terminates the backup on every iOS 26 device. | ||
| # Respond with the current free space (matching get_free_disk_space) so the |
Owner
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Problem
iOS 26 introduced two MobileBackup2 regressions that prevent any backup from completing.
1.
DLMessagePurgeDiskSpaceunconditionally raisesNotEnoughDiskSpaceErroriOS 26 sends
DLMessagePurgeDiskSpaceas a routine pre-backup space probe before the transfer begins — not as an error condition indicating the host is actually full. The current handler raisesNotEnoughDiskSpaceErrorunconditionally, which terminates every backup on iOS 26 before a single file transfers.2.
DLMessageGetFreeDiskSpace— iOS 26 rejects hosts with ErrorCode 105iOS 26 compares the reported free space against an inflated internal backup-size estimate and returns
ErrorCode: 105("insufficient free disk space") even when the host has >100 GB free. This causes the device to abort the backup immediately after the space handshake.Fix
purge_disk_space: respond with the actual free space (same format asget_free_disk_space) instead of raising. This matches howDLMessageGetFreeDiskSpaceis handled and satisfies the iOS 26 probe.get_free_disk_space: reportmax(actual, 1 TB)so the host always passes iOS 26's threshold check. If the backup genuinely exceeds available disk space it will fail mid-transfer — the correct, recoverable behaviour.Also removes the now-unused
NotEnoughDiskSpaceErrorimport.Testing
Verified against an iPhone running iOS 26.4.2. Before the patch: backup failed immediately with
NotEnoughDiskSpaceError/ ErrorCode 105. After: backup completes successfully.Related
download_filesre: iOS 17 beta — iOS tends to send protocol messages in new versions that the library hasn't seen before.