AArch64 Hyper-V: no init

Launching a VM with OpenHCL (without Trusted Launch) fails (as in the VM doesn't even run) with a "no init" error captured from Hyper-V-Worker-Admin.

Host Windows: 26340.9233
OpenVMM: 1b873556b46fec154cf552cbbf3b779ab03068b7

Error log:

'Test' has encountered a fatal error.  The guest operating system reported that it failed with the following error codes: ErrorCode0: 0x0, ErrorCode1: 0x0, ErrorCode2: 0x0, ErrorCode3: 0x0, ErrorCode4: 0x0,  PreOSId: 0, VTL 0x2.  If the problem persists, contact Product Support for the guest operating system.  (Virtual machine ID BE32FEC1-D2B7-4CE0-96C4-B0E5AEA740BB)

Guest message:
[    0.006245] clocksource: Switched to clocksource arch_sys_counter
[    0.006428] NET: Registered PF_UNIX/PF_LOCAL protocol family
[    0.006507] Unpacking initramfs...
[    0.010202] workingset: timestamp_bits=62 max_order=13 bucket_order=0
[    0.010238] io scheduler mq-deadline registered
[    0.010337] printk: legacy console [ttynull0] enabled
[    0.010420] hv_vmbus: registering driver uio_hv_generic
[    0.010459] VFIO - User Level meta-driver version: 0.3
[    0.010472] vfio_pci: add [1414:00ba[ffffffff:ffffffff]] class 0x000000/00000000
[    0.010480] SMCCC: SOC_ID: ARCH_SOC_ID not implemented, skipping ....
[    0.010513] not using the register page
[    0.010573] armv8-pmu pmu: hw perfevents: no irqs for PMU, sampling events not supported
[    0.010601] hw perfevents: enabled with armv8_pmuv3 PMU driver, 7 (0,8000003f) counters available
[    0.010626] NET: Registered PF_VSOCK protocol family
[    0.010628] hv_vmbus: registering driver hv_sock
[    0.016271] clk: Disabling unused clocks
[    0.016273] PM: genpd: Disabling unused power domains
[    0.067090] Initramfs unpacking failed: write error
[    0.067495] Freeing initrd memory: 7840K
[    0.067529] check access for rdinit=/underhill-init failed: -2, ignoring
[    0.067555] VFS: Mounted root (tmpfs filesystem) readonly on device 0:14.
[    0.067557] devtmpfs: error mounting -2
[    0.067626] Freeing unused kernel memory: 1024K
[    0.076318] Run /sbin/init as init process
[    0.076321]   with arguments:
[    0.076321]     /sbin/init
[    0.076322]   with environment:
[    0.076323]     HOME=/
[    0.076324]     TERM=linux
[    0.076325]     idle=halt
[    0.076326]     tsc=reliable
[    0.076327]     unknown_nmi_panic=1
[    0.076327]     OPENHCL_NVME_VFIO=1
[    0.076328]     MIMALLOC_ARENA_EAGER_COMMIT=0
[    0.076329]     acpi=off
[    0.076330]     OPENHCL_CONFIDENTIAL_DEBUG=1
[    0.076331]     OPENHCL_NVME_KEEP_ALIVE=nohost,privatepool
[    0.076332]     OPENHCL_IGVM_VTL2_GPA_POOL_CONFIG=release
[    0.076336] Run /etc/init as init process
[    0.076337]   with arguments:
[    0.076338]     /etc/init
[    0.076339]   with environment:
[    0.076340]     HOME=/
[    0.076340]     TERM=linux
[    0.076341]     idle=halt
[    0.076342]     tsc=reliable
[    0.076343]     unknown_nmi_panic=1
[    0.076344]     OPENHCL_NVME_VFIO=1
[    0.076344]     MIMALLOC_ARENA_EAGER_COMMIT=0
[    0.076345]     acpi=off
[    0.076346]     OPENHCL_CONFIDENTIAL_DEBUG=1
[    0.076347]     OPENHCL_NVME_KEEP_ALIVE=nohost,privatepool
[    0.076348]     OPENHCL_IGVM_VTL2_GPA_POOL_CONFIG=release
[    0.076350] Run /bin/init as init process
[    0.076351]   with arguments:
[    0.076351]     /bin/init
[    0.076352]   with environment:
[    0.076353]     HOME=/
[    0.076354]     TERM=linux
[    0.076355]     idle=halt
[    0.076355]     tsc=reliable
[    0.076356]     unknown_nmi_panic=1
[    0.076357]     OPENHCL_NVME_VFIO=1
[    0.076358]     MIMALLOC_ARENA_EAGER_COMMIT=0
[    0.076359]     acpi=off
[    0.076360]     OPENHCL_CONFIDENTIAL_DEBUG=1
[    0.076360]     OPENHCL_NVME_KEEP_ALIVE=nohost,privatepool
[    0.076361]     OPENHCL_IGVM_VTL2_GPA_POOL_CONFIG=release
[    0.076364] Run /bin/sh as init process
[    0.076364]   with arguments:
[    0.076365]     /bin/sh
[    0.076366]   with environment:
[    0.076367]     HOME=/
[    0.076368]     TERM=linux
[    0.076368]     idle=halt
[    0.076369]     tsc=reliable
[    0.076370]     unknown_nmi_panic=1
[    0.076371]     OPENHCL_NVME_VFIO=1
[    0.076372]     MIMALLOC_ARENA_EAGER_COMMIT=0
[    0.076373]     acpi=off
[    0.076373]     OPENHCL_CONFIDENTIAL_DEBUG=1
[    0.076374]     OPENHCL_NVME_KEEP_ALIVE=nohost,privatepool
[    0.076375]     OPENHCL_IGVM_VTL2_GPA_POOL_CONFIG=release
[    0.076377] Kernel panic - not syncing: No working init found.  Try passing init= option to kernel. See Linux Documentation/admin-guide/init.rst for guidance.
[    0.076379] Kernel Offset: disabled
[    0.076380] CPU features: 0x040000,0000e000,42306281,04005a03
[    0.076382] Memory Limit: none