diff --git a/include/os/freebsd/linux/compiler.h b/include/os/freebsd/linux/compiler.h
index d76050378..05e93efa6 100644
--- a/include/os/freebsd/linux/compiler.h
+++ b/include/os/freebsd/linux/compiler.h
@@ -68,7 +68,7 @@
 #define	noinline			__noinline
 #define	____cacheline_aligned		__aligned(CACHE_LINE_SIZE)
 
-#ifndef _KERNEL
+#if !defined(_KERNEL) && !defined(_STANDALONE)
 #define	likely(x)			__builtin_expect(!!(x), 1)
 #define	unlikely(x)			__builtin_expect(!!(x), 0)
 #endif
diff --git a/include/os/freebsd/spl/rpc/xdr.h b/include/os/freebsd/spl/rpc/xdr.h
index 59d5e425b..c98466e9d 100644
--- a/include/os/freebsd/spl/rpc/xdr.h
+++ b/include/os/freebsd/spl/rpc/xdr.h
@@ -33,7 +33,7 @@
 #include <rpc/types.h>
 #include_next <rpc/xdr.h>
 
-#ifndef _KERNEL
+#if !defined(_KERNEL) && !defined(_STANDALONE)
 
 #include <assert.h>
 
@@ -66,6 +66,6 @@ xdrmem_control(XDR *xdrs, int request, void *info)
 	    xdrmem_control((xdrs), (req), (op)) :			\
 	    (*(xdrs)->x_ops->x_control)(xdrs, req, op))
 
-#endif	/* !_KERNEL */
+#endif	/* !_KERNEL && !_STANDALONE */
 
 #endif	/* !_OPENSOLARIS_RPC_XDR_H_ */
diff --git a/include/os/freebsd/spl/sys/atomic.h b/include/os/freebsd/spl/sys/atomic.h
index 4227e5f7d..1a68bfc4d 100644
--- a/include/os/freebsd/spl/sys/atomic.h
+++ b/include/os/freebsd/spl/sys/atomic.h
@@ -29,6 +29,8 @@
 #ifndef _OPENSOLARIS_SYS_ATOMIC_H_
 #define	_OPENSOLARIS_SYS_ATOMIC_H_
 
+#ifndef _STANDALONE
+
 #include <sys/types.h>
 #include <machine/atomic.h>
 
@@ -179,4 +181,13 @@ atomic_cas_ptr(volatile void *target, void *cmp,  void *newval)
 }
 #endif	/* !defined(COMPAT_32BIT) && defined(__LP64__) */
 
+#else /* _STANDALONE */
+/*
+ * sometimes atomic_add_64 is defined, sometimes not, but the
+ * following is always right for the boot loader.
+ */
+#undef atomic_add_64
+#define	atomic_add_64(ptr, val) *(ptr) += val
+#endif /* !_STANDALONE */
+
 #endif	/* !_OPENSOLARIS_SYS_ATOMIC_H_ */
diff --git a/include/os/freebsd/spl/sys/byteorder.h b/include/os/freebsd/spl/sys/byteorder.h
index ae767242b..0b3d01eb3 100644
--- a/include/os/freebsd/spl/sys/byteorder.h
+++ b/include/os/freebsd/spl/sys/byteorder.h
@@ -80,10 +80,11 @@
 #define	BE_64(x)	BSWAP_64(x)
 #endif
 
+#if !defined(_STANDALONE)
 #if BYTE_ORDER == _BIG_ENDIAN
 #define	htonll(x)	BMASK_64(x)
 #define	ntohll(x)	BMASK_64(x)
-#else
+#else /* BYTE_ORDER == _LITTLE_ENDIAN */
 #ifndef __LP64__
 static __inline__ uint64_t
 htonll(uint64_t n)
@@ -96,11 +97,12 @@ ntohll(uint64_t n)
 {
 	return ((((uint64_t)ntohl(n)) << 32) + ntohl(n >> 32));
 }
-#else
+#else	/* !__LP64__ */
 #define	htonll(x)	BSWAP_64(x)
 #define	ntohll(x)	BSWAP_64(x)
-#endif
-#endif
+#endif	/* __LP64__ */
+#endif	/* BYTE_ORDER */
+#endif	/* _STANDALONE */
 
 #define	BE_IN32(xa)	htonl(*((uint32_t *)(void *)(xa)))
 
diff --git a/include/os/freebsd/spl/sys/ccompile.h b/include/os/freebsd/spl/sys/ccompile.h
index bffe6d21e..cf1e0a8a6 100644
--- a/include/os/freebsd/spl/sys/ccompile.h
+++ b/include/os/freebsd/spl/sys/ccompile.h
@@ -113,9 +113,9 @@ extern "C" {
 #define	__VPRINTFLIKE(__n)	__sun_attr__((__VPRINTFLIKE__(__n)))
 #define	__KPRINTFLIKE(__n)	__sun_attr__((__KPRINTFLIKE__(__n)))
 #define	__KVPRINTFLIKE(__n)	__sun_attr__((__KVPRINTFLIKE__(__n)))
-#ifdef _KERNEL
+#if	defined(_KERNEL) || defined(_STANDALONE)
 #define	__NORETURN		__sun_attr__((__noreturn__))
-#endif
+#endif /* _KERNEL || _STANDALONE */
 #define	__CONST			__sun_attr__((__const__))
 #define	__PURE			__sun_attr__((__pure__))
 
@@ -174,7 +174,7 @@ typedef int enum_t;
 #define	__exit
 #endif
 
-#ifdef _KERNEL
+#if defined(_KERNEL) || defined(_STANDALONE)
 #define	param_set_charp(a, b) (0)
 #define	ATTR_UID AT_UID
 #define	ATTR_GID AT_GID
@@ -183,9 +183,15 @@ typedef int enum_t;
 #define	ATTR_CTIME	AT_CTIME
 #define	ATTR_MTIME	AT_MTIME
 #define	ATTR_ATIME	AT_ATIME
+#if defined(_STANDALONE)
+#define	vmem_free kmem_free
+#define	vmem_zalloc kmem_zalloc
+#define	vmem_alloc kmem_zalloc
+#else
 #define	vmem_free zfs_kmem_free
 #define	vmem_zalloc(size, flags) zfs_kmem_alloc(size, flags | M_ZERO)
 #define	vmem_alloc zfs_kmem_alloc
+#endif
 #define	MUTEX_NOLOCKDEP 0
 #define	RW_NOLOCKDEP 0
 
diff --git a/include/os/freebsd/spl/sys/cmn_err.h b/include/os/freebsd/spl/sys/cmn_err.h
index 00d686439..ba4cff37d 100644
--- a/include/os/freebsd/spl/sys/cmn_err.h
+++ b/include/os/freebsd/spl/sys/cmn_err.h
@@ -52,42 +52,33 @@ extern "C" {
 /*PRINTFLIKE2*/
 extern void cmn_err(int, const char *, ...)
     __KPRINTFLIKE(2);
-#pragma rarely_called(cmn_err)
 
 extern void vzcmn_err(zoneid_t, int, const char *, __va_list)
     __KVPRINTFLIKE(3);
-#pragma rarely_called(vzcmn_err)
 
 extern void vcmn_err(int, const char *, __va_list)
     __KVPRINTFLIKE(2);
-#pragma rarely_called(vcmn_err)
 
 /*PRINTFLIKE3*/
 extern void zcmn_err(zoneid_t, int, const char *, ...)
     __KPRINTFLIKE(3);
-#pragma rarely_called(zcmn_err)
 
 extern void vzprintf(zoneid_t, const char *, __va_list)
     __KVPRINTFLIKE(2);
-#pragma rarely_called(vzprintf)
 
 /*PRINTFLIKE2*/
 extern void zprintf(zoneid_t, const char *, ...)
     __KPRINTFLIKE(2);
-#pragma rarely_called(zprintf)
 
 extern void vuprintf(const char *, __va_list)
     __KVPRINTFLIKE(1);
-#pragma rarely_called(vuprintf)
 
 /*PRINTFLIKE1*/
 extern void panic(const char *, ...)
     __KPRINTFLIKE(1) __NORETURN;
-#pragma rarely_called(panic)
 
 extern void vpanic(const char *, __va_list)
     __KVPRINTFLIKE(1) __NORETURN;
-#pragma rarely_called(vpanic)
 
 #endif /* !_ASM */
 
diff --git a/include/os/freebsd/spl/sys/condvar.h b/include/os/freebsd/spl/sys/condvar.h
index a634ab6b6..9b1893bcb 100644
--- a/include/os/freebsd/spl/sys/condvar.h
+++ b/include/os/freebsd/spl/sys/condvar.h
@@ -36,6 +36,7 @@
 #include <sys/spl_condvar.h>
 #include <sys/mutex.h>
 #include <sys/time.h>
+#include <sys/errno.h>
 
 /*
  * cv_timedwait() is similar to cv_wait() except that it additionally expects
diff --git a/include/os/freebsd/spl/sys/kmem.h b/include/os/freebsd/spl/sys/kmem.h
index 28c65e74a..dc3b4f5d7 100644
--- a/include/os/freebsd/spl/sys/kmem.h
+++ b/include/os/freebsd/spl/sys/kmem.h
@@ -29,6 +29,7 @@
 #ifndef _OPENSOLARIS_SYS_KMEM_H_
 #define	_OPENSOLARIS_SYS_KMEM_H_
 
+#ifdef _KERNEL
 #include <sys/param.h>
 #include <sys/malloc.h>
 #include <sys/vmem.h>
@@ -93,5 +94,14 @@ void *calloc(size_t n, size_t s);
 	zfs_kmem_alloc((size), (kmflags) | M_ZERO)
 #define	kmem_free(buf, size)		zfs_kmem_free((buf), (size))
 
+#endif	/* _KERNEL */
+
+#ifdef _STANDALONE
+/*
+ * At the moment, we just need it for the type. We redirect the alloc/free
+ * routines to the usual Free and Malloc in that environment.
+ */
+typedef int kmem_cache_t;
+#endif /* _STANDALONE */
 
 #endif	/* _OPENSOLARIS_SYS_KMEM_H_ */
diff --git a/include/os/freebsd/spl/sys/kmem_cache.h b/include/os/freebsd/spl/sys/kmem_cache.h
index d8e0349e4..9eec3b458 100644
--- a/include/os/freebsd/spl/sys/kmem_cache.h
+++ b/include/os/freebsd/spl/sys/kmem_cache.h
@@ -30,6 +30,7 @@
 #ifndef _SPL_KMEM_CACHE_H
 #define	_SPL_KMEM_CACHE_H
 
+#ifdef _KERNEL
 #include <sys/taskq.h>
 
 /* kmem move callback return values */
@@ -46,4 +47,6 @@ extern void spl_kmem_cache_set_move(kmem_cache_t *,
 
 #define	kmem_cache_set_move(skc, move)	spl_kmem_cache_set_move(skc, move)
 
+#endif /* _KERNEL */
+
 #endif
diff --git a/include/os/freebsd/spl/sys/kstat.h b/include/os/freebsd/spl/sys/kstat.h
index b0a1c9689..f5157c7f4 100644
--- a/include/os/freebsd/spl/sys/kstat.h
+++ b/include/os/freebsd/spl/sys/kstat.h
@@ -23,8 +23,11 @@
 
 #ifndef _SPL_KSTAT_H
 #define	_SPL_KSTAT_H
+
 #include <sys/types.h>
+#ifndef _STANDALONE
 #include <sys/sysctl.h>
+#endif
 struct list_head {};
 #include <sys/mutex.h>
 #include <sys/proc.h>
@@ -128,9 +131,10 @@ struct kstat_s {
 	kstat_raw_ops_t	ks_raw_ops;		/* ops table for raw type */
 	char		*ks_raw_buf;		/* buf used for raw ops */
 	size_t		ks_raw_bufsize;		/* size of raw ops buffer */
+#ifndef _STANDALONE
 	struct sysctl_ctx_list ks_sysctl_ctx;
 	struct sysctl_oid *ks_sysctl_root;
-
+#endif /* _STANDALONE */
 };
 
 typedef struct kstat_named_s {
@@ -215,10 +219,16 @@ extern void kstat_runq_exit(kstat_io_t *);
     __kstat_set_seq_raw_ops(k, h, d, a)
 #define	kstat_set_raw_ops(k, h, d, a) \
     __kstat_set_raw_ops(k, h, d, a)
+#ifndef _STANDALONE
 #define	kstat_create(m, i, n, c, t, s, f) \
     __kstat_create(m, i, n, c, t, s, f)
 
 #define	kstat_install(k)		__kstat_install(k)
 #define	kstat_delete(k)			__kstat_delete(k)
+#else
+#define	kstat_create(m, i, n, c, t, s, f)	((kstat_t *)0)
+#define	kstat_install(k)
+#define	kstat_delete(k)
+#endif
 
 #endif  /* _SPL_KSTAT_H */
diff --git a/include/os/freebsd/spl/sys/proc.h b/include/os/freebsd/spl/sys/proc.h
index a455cfbab..8583df509 100644
--- a/include/os/freebsd/spl/sys/proc.h
+++ b/include/os/freebsd/spl/sys/proc.h
@@ -41,7 +41,7 @@
 #include <sys/kmem.h>
 #include <sys/malloc.h>
 
-
+#ifdef _KERNEL
 #define	CPU		curcpu
 #define	minclsyspri	PRIBIO
 #define	defclsyspri minclsyspri
@@ -111,4 +111,5 @@ zfs_proc_is_caller(proc_t *p)
 	return (p == curproc);
 }
 
+#endif	/* _KERNEL */
 #endif	/* _OPENSOLARIS_SYS_PROC_H_ */
diff --git a/include/os/freebsd/spl/sys/procfs_list.h b/include/os/freebsd/spl/sys/procfs_list.h
index da13f0387..4bc603756 100644
--- a/include/os/freebsd/spl/sys/procfs_list.h
+++ b/include/os/freebsd/spl/sys/procfs_list.h
@@ -25,6 +25,8 @@
 #ifndef	_SPL_PROCFS_LIST_H
 #define	_SPL_PROCFS_LIST_H
 
+#ifndef _STANDALONE
+
 #include <sys/kstat.h>
 #include <sys/mutex.h>
 
@@ -64,4 +66,8 @@ void procfs_list_uninstall(procfs_list_t *procfs_list);
 void procfs_list_destroy(procfs_list_t *procfs_list);
 void procfs_list_add(procfs_list_t *procfs_list, void *p);
 
+#else
+typedef int procfs_list_t;
+#endif /* !_STANDALONE */
+
 #endif	/* _SPL_PROCFS_LIST_H */
diff --git a/include/os/freebsd/spl/sys/sig.h b/include/os/freebsd/spl/sys/sig.h
index 426a9e827..a4d440d38 100644
--- a/include/os/freebsd/spl/sys/sig.h
+++ b/include/os/freebsd/spl/sys/sig.h
@@ -29,6 +29,8 @@
 #ifndef _OPENSOLARIS_SYS_SIG_H_
 #define	_OPENSOLARIS_SYS_SIG_H_
 
+#ifndef _STANDALONE
+
 #include_next <sys/signal.h>
 #include <sys/param.h>
 #include <sys/lock.h>
@@ -62,4 +64,7 @@ issig(int why)
 	}
 	return (0);
 }
+
+#endif /* !_STANDALONE */
+
 #endif	/* _OPENSOLARIS_SYS_SIG_H_ */
diff --git a/include/os/freebsd/spl/sys/sysmacros.h b/include/os/freebsd/spl/sys/sysmacros.h
index 5afca1044..2d0164cb1 100644
--- a/include/os/freebsd/spl/sys/sysmacros.h
+++ b/include/os/freebsd/spl/sys/sysmacros.h
@@ -31,6 +31,7 @@
 #define	_SYS_SYSMACROS_H
 
 #include <sys/param.h>
+#include <sys/systm.h>
 #include <sys/isa_defs.h>
 #include <sys/libkern.h>
 #include <sys/zone.h>
@@ -71,7 +72,11 @@ extern "C" {
 #define	DIV_ROUND_UP(n, d)	(((n) + (d) - 1) / (d))
 #endif
 
+#ifdef _STANDALONE
+#define	boot_ncpus 1
+#else /* _STANDALONE */
 #define	boot_ncpus mp_ncpus
+#endif /* _STANDALONE */
 #define	kpreempt_disable() critical_enter()
 #define	kpreempt_enable() critical_exit()
 #define	CPU_SEQID curcpu
@@ -319,7 +324,7 @@ extern unsigned char bcd_to_byte[256];
 
 /* avoid any possibility of clashing with <stddef.h> version */
 
-#define	offsetof(s, m)	((size_t)(&(((s *)0)->m)))
+#define	offsetof(type, field)	__offsetof(type, field)
 #endif
 
 /*
diff --git a/include/os/freebsd/spl/sys/taskq.h b/include/os/freebsd/spl/sys/taskq.h
index 200f9e838..3040549e0 100644
--- a/include/os/freebsd/spl/sys/taskq.h
+++ b/include/os/freebsd/spl/sys/taskq.h
@@ -26,6 +26,8 @@
 #ifndef	_SYS_TASKQ_H
 #define	_SYS_TASKQ_H
 
+#ifdef _KERNEL
+
 #include <sys/types.h>
 #include <sys/proc.h>
 #include <sys/taskqueue.h>
@@ -112,4 +114,11 @@ void	taskq_resume(taskq_t *);
 }
 #endif
 
+#endif /* _KERNEL */
+
+#ifdef _STANDALONE
+typedef int taskq_ent_t;
+#define	taskq_init_ent(x)
+#endif /* _STANDALONE */
+
 #endif	/* _SYS_TASKQ_H */
diff --git a/include/os/freebsd/spl/sys/uio.h b/include/os/freebsd/spl/sys/uio.h
index 2b4357a30..cb577df10 100644
--- a/include/os/freebsd/spl/sys/uio.h
+++ b/include/os/freebsd/spl/sys/uio.h
@@ -29,6 +29,8 @@
 #ifndef _OPENSOLARIS_SYS_UIO_H_
 #define	_OPENSOLARIS_SYS_UIO_H_
 
+#ifndef _STANDALONE
+
 #include_next <sys/uio.h>
 #include <sys/_uio.h>
 #include <sys/debug.h>
@@ -107,4 +109,6 @@ uio_index_at_offset(uio_t *uio, offset_t off, uint_t *vec_idx)
 	return (off);
 }
 
+#endif /* !_STANDALONE */
+
 #endif	/* !_OPENSOLARIS_SYS_UIO_H_ */
diff --git a/include/sys/nvpair.h b/include/sys/nvpair.h
index e8567933d..b0be8bd7a 100644
--- a/include/sys/nvpair.h
+++ b/include/sys/nvpair.h
@@ -62,7 +62,7 @@ typedef enum {
 	DATA_TYPE_UINT8,
 	DATA_TYPE_BOOLEAN_ARRAY,
 	DATA_TYPE_INT8_ARRAY,
-#if !defined(_KERNEL)
+#if !defined(_KERNEL) && !defined(_STANDALONE)
 	DATA_TYPE_UINT8_ARRAY,
 	DATA_TYPE_DOUBLE
 #else
@@ -191,7 +191,7 @@ int nvlist_add_uint64_array(nvlist_t *, const char *, uint64_t *, uint_t);
 int nvlist_add_string_array(nvlist_t *, const char *, char *const *, uint_t);
 int nvlist_add_nvlist_array(nvlist_t *, const char *, nvlist_t **, uint_t);
 int nvlist_add_hrtime(nvlist_t *, const char *, hrtime_t);
-#if !defined(_KERNEL)
+#if !defined(_KERNEL) && !defined(_STANDALONE)
 int nvlist_add_double(nvlist_t *, const char *, double);
 #endif
 
@@ -228,7 +228,7 @@ int nvlist_lookup_nvlist_array(nvlist_t *, const char *,
     nvlist_t ***, uint_t *);
 int nvlist_lookup_hrtime(nvlist_t *, const char *, hrtime_t *);
 int nvlist_lookup_pairs(nvlist_t *, int, ...);
-#if !defined(_KERNEL)
+#if !defined(_KERNEL) && !defined(_STANDALONE)
 int nvlist_lookup_double(nvlist_t *, const char *, double *);
 #endif
 
@@ -269,7 +269,7 @@ int nvpair_value_uint64_array(nvpair_t *, uint64_t **, uint_t *);
 int nvpair_value_string_array(nvpair_t *, char ***, uint_t *);
 int nvpair_value_nvlist_array(nvpair_t *, nvlist_t ***, uint_t *);
 int nvpair_value_hrtime(nvpair_t *, hrtime_t *);
-#if !defined(_KERNEL)
+#if !defined(_KERNEL) && !defined(_STANDALONE)
 int nvpair_value_double(nvpair_t *, double *);
 #endif
 
diff --git a/include/sys/zfs_context.h b/include/sys/zfs_context.h
index d9f5ed580..9f637036e 100644
--- a/include/sys/zfs_context.h
+++ b/include/sys/zfs_context.h
@@ -32,7 +32,15 @@
 extern "C" {
 #endif
 
-#ifdef __KERNEL__
+/*
+ * This code compiles in three different contexts. When __KERNEL__ is defined,
+ * the code uses "unix-like" kernel interfaces. When _STANDALONE is defined, the
+ * code is running in a reduced capacity environment of the boot loader which is
+ * generally a subset of both POSIX and kernel interfaces (with a few unique
+ * interfaces too). When neither are defined, it's in a userland POSIX or
+ * similar environment.
+ */
+#if defined(__KERNEL__) || defined(_STANDALONE)
 #include <sys/note.h>
 #include <sys/types.h>
 #include <sys/atomic.h>
@@ -65,7 +73,7 @@ extern "C" {
 #include <sys/procfs_list.h>
 #include <sys/mod.h>
 #include <sys/zfs_context_os.h>
-#else /* _KERNEL */
+#else /* _KERNEL || _STANDALONE */
 
 #define	_SYS_MUTEX_H
 #define	_SYS_RWLOCK_H
@@ -759,7 +767,7 @@ extern int kmem_cache_reap_active(void);
 #define	__init
 #define	__exit
 
-#endif /* _KERNEL */
+#endif  /* _KERNEL || _STANDALONE */
 
 #ifdef __cplusplus
 };
diff --git a/lib/libspl/include/os/freebsd/sys/param.h b/lib/libspl/include/os/freebsd/sys/param.h
index 7c23b6705..cb5260ea3 100644
--- a/lib/libspl/include/os/freebsd/sys/param.h
+++ b/lib/libspl/include/os/freebsd/sys/param.h
@@ -45,10 +45,6 @@
  */
 #define	MAXNAMELEN	256
 
-#ifndef IN_BASE
-#define	UID_NOBODY	60001		/* user ID no body */
-#define	GID_NOBODY	UID_NOBODY
-#endif
 #define	UID_NOACCESS	60002		/* user ID no access */
 
 #define	MAXUID		UINT32_MAX	/* max user id */
diff --git a/module/os/freebsd/spl/list.c b/module/os/freebsd/spl/list.c
index 8796be4a9..0f5ae6291 100644
--- a/module/os/freebsd/spl/list.c
+++ b/module/os/freebsd/spl/list.c
@@ -27,10 +27,10 @@
  * Generic doubly-linked list implementation
  */
 
+#include <sys/param.h>
 #include <sys/list.h>
 #include <sys/list_impl.h>
 #include <sys/types.h>
-#include <sys/sysmacros.h>
 #include <sys/debug.h>
 
 #define	list_d2l(a, obj) ((list_node_t *)(((char *)obj) + (a)->list_offset))