Files
vphone-cli/sources
zqxwceandClaude Opus 4.8 8781e20c76 cfw: iBoot: disable skywalk fsw netagents on iOS 18 (if_attach_nx=0x3)
iOS 18.6.2 userland on the 26.1 vphone600 kernel has no working DNS: the
guest gets a correct resolver config (DHCP hands out 192.168.64.1, which
configd propagates to State:/Network/Global/DNS) and the path works (raw
UDP DNS to the gateway succeeds), but getaddrinfo fails EAI_NONAME because
mDNSResponder crash-loops. Every crash is identical: EXC_BREAKPOINT in
os_channel_create_extended, hit from Network.framework flow setup
(nw_channel_create_with_attributes). That is a skywalk userspace-channel
trap: the 26.1 kernel advertises skywalk, Network.framework tries to create
a flowswitch channel for its DNS flow, the channel-create syscall trips a
fatal trap in the 18.6.2 libsystem_kernel, and the resolver daemon dies.
26.x userland handles this path; 18.6.2 does not.

Fix: set boot-arg if_attach_nx=0x3 (SKYWALK_NETWORKING_BSD_ONLY =
IF_ATTACH_NX_NETIF_COMPAT | IF_ATTACH_NX_FLOWSWITCH) on iOS 18 bases. This
keeps the netif + flowswitch nexus (interface/host stack unaffected) but
leaves the FSW_TRANSPORT/IP netagents unset, so Network.framework uses the
BSD-socket path and mDNSResponder never creates the crashing channel. The
kernel boot-args come from the patched iBoot (kern.bootargs matches
IBootPatcher.bootArgs), so the arg is baked into the iBEC/LLB boot-args
patch, not the host NVRAM (which iBoot overrides).

- IBootPatcher gains `extraBootArgs`, inserted before the trailing %s in
  the patched boot-args string (ibec/llb).
- FirmwarePipeline sets extraBootArgs="if_attach_nx=0x3" for iOS 18 bases
  (iosBaseIs18), empty otherwise, on the iBEC and LLB factories.

Gated to iOS 18 bases: 26.x keeps the stock boot-args and is untouched.
Validated at runtime first (setting net.link.generic.system.enable_netagent
=0 makes DNS resolve reliably), then confirmed end-to-end on a fresh
17,3_18.6.2_22G100 jb restore: kern.bootargs shows if_attach_nx=0x3 and
DNS/networking works.

Documented in research/0_binary_patch_comparison.md (iBEC/LLB boot-args row).

Co-Authored-By: Claude Opus 4.8 <[email protected]>
Claude-Session: https://claude.ai/code/session_01Q7gbWrtKLu8rFGmpXHmu9t
2026-07-13 15:40:44 +03:00
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2026-03-11 00:42:26 +08:00
2026-03-11 00:42:26 +08:00