diff --git a/usr.sbin/bhyve/aarch64/vmexit.c b/usr.sbin/bhyve/aarch64/vmexit.c
index a458dfc76646..ecbbcae36187 100644
--- a/usr.sbin/bhyve/aarch64/vmexit.c
+++ b/usr.sbin/bhyve/aarch64/vmexit.c
@@ -43,6 +43,7 @@
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <unistd.h>
 
 #include <vmmapi.h>
 
@@ -132,6 +133,11 @@ vmexit_debug(struct vmctx *ctx __unused, struct vcpu *vcpu,
     struct vm_run *vmrun __unused)
 {
 	gdb_cpu_suspend(vcpu);
+	/*
+	 * XXX-MJ sleep for a short period to avoid chewing up the CPU in the
+	 * window between activation of the vCPU thread and the STARTUP IPI.
+	 */
+	usleep(1000);
 	return (VMEXIT_CONTINUE);
 }
 
@@ -243,7 +249,8 @@ vmexit_smccc(struct vmctx *ctx, struct vcpu *vcpu, struct vm_run *vmrun)
 			how = VM_SUSPEND_POWEROFF;
 		else
 			how = VM_SUSPEND_RESET;
-		vm_suspend(ctx, how);
+		error = vm_suspend(ctx, how);
+		assert(error == 0 || errno == EALREADY);
 		break;
 	default:
 		break;
diff --git a/usr.sbin/bhyve/amd64/bhyverun_machdep.c b/usr.sbin/bhyve/amd64/bhyverun_machdep.c
index 17c97ab994ba..41ac946a20f8 100644
--- a/usr.sbin/bhyve/amd64/bhyverun_machdep.c
+++ b/usr.sbin/bhyve/amd64/bhyverun_machdep.c
@@ -37,6 +37,7 @@
 #include "acpi.h"
 #include "atkbdc.h"
 #include "bhyverun.h"
+#include "bootrom.h"
 #include "config.h"
 #include "debug.h"
 #include "e820.h"
@@ -237,6 +238,18 @@ bhyve_optparse(int argc, char **argv)
 			bhyve_usage(1);
 		}
 	}
+
+	/* Handle backwards compatibility aliases in config options. */
+	if (get_config_value("lpc.bootrom") != NULL &&
+	    get_config_value("bootrom") == NULL) {
+		warnx("lpc.bootrom is deprecated, use '-o bootrom' instead");
+		set_config_value("bootrom", get_config_value("lpc.bootrom"));
+	}
+	if (get_config_value("lpc.bootvars") != NULL &&
+	    get_config_value("bootvars") == NULL) {
+		warnx("lpc.bootvars is deprecated, use '-o bootvars' instead");
+		set_config_value("bootvars", get_config_value("lpc.bootvars"));
+	}
 }
 
 void
@@ -287,7 +300,7 @@ bhyve_start_vcpu(struct vcpu *vcpu, bool bsp)
 	int error;
 
 	if (bsp) {
-		if (lpc_bootrom()) {
+		if (bootrom_boot()) {
 			error = vm_set_capability(vcpu,
 			    VM_CAP_UNRESTRICTED_GUEST, 1);
 			if (error != 0) {
@@ -328,6 +341,9 @@ bhyve_init_platform(struct vmctx *ctx, struct vcpu *bsp __unused)
 	rtc_init(ctx);
 	sci_init(ctx);
 	error = e820_init(ctx);
+	if (error != 0)
+		return (error);
+	error = bootrom_loadrom(ctx);
 	if (error != 0)
 		return (error);
 
@@ -351,7 +367,7 @@ bhyve_init_platform_late(struct vmctx *ctx, struct vcpu *bsp __unused)
 	if (error != 0)
 		return (error);
 
-	if (lpc_bootrom() && strcmp(lpc_fwcfg(), "bhyve") == 0)
+	if (bootrom_boot() && strcmp(lpc_fwcfg(), "bhyve") == 0)
 		fwctl_init();
 
 	if (get_config_bool("acpi_tables")) {
diff --git a/usr.sbin/bhyve/amd64/ioapic.c b/usr.sbin/bhyve/amd64/ioapic.c
index 9ad1c501fbae..494fb0c7ae82 100644
--- a/usr.sbin/bhyve/amd64/ioapic.c
+++ b/usr.sbin/bhyve/amd64/ioapic.c
@@ -33,6 +33,7 @@
 #include <machine/vmm.h>
 #include <vmmapi.h>
 
+#include "bootrom.h"
 #include "ioapic.h"
 #include "pci_emul.h"
 #include "pci_lpc.h"
@@ -72,7 +73,7 @@ ioapic_pci_alloc_irq(struct pci_devinst *pi)
 
 	if (pci_pins == 0)
 		return (-1);
-	if (lpc_bootrom()) {
+	if (bootrom_boot()) {
 		/* For external bootrom use fixed mapping. */
 		return (16 + (4 + pi->pi_slot + pi->pi_lintr.pin) % 8);
 	}
diff --git a/usr.sbin/bhyve/amd64/pci_irq.c b/usr.sbin/bhyve/amd64/pci_irq.c
index 7e1aee7fbb1d..fea6d9a2591c 100644
--- a/usr.sbin/bhyve/amd64/pci_irq.c
+++ b/usr.sbin/bhyve/amd64/pci_irq.c
@@ -38,6 +38,7 @@
 #include <vmmapi.h>
 
 #include "acpi.h"
+#include "bootrom.h"
 #include "inout.h"
 #include "ioapic.h"
 #include "pci_emul.h"
@@ -205,7 +206,7 @@ pirq_alloc_pin(struct pci_devinst *pi)
 
 	pirq_cold = 0;
 
-	if (lpc_bootrom()) {
+	if (bootrom_boot()) {
 		/* For external bootrom use fixed mapping. */
 		best_pin = (4 + pi->pi_slot + pi->pi_lintr.pin) % 8;
 	} else {
diff --git a/usr.sbin/bhyve/amd64/pci_lpc.c b/usr.sbin/bhyve/amd64/pci_lpc.c
index 57d2333edcc6..ed41a800a2ea 100644
--- a/usr.sbin/bhyve/amd64/pci_lpc.c
+++ b/usr.sbin/bhyve/amd64/pci_lpc.c
@@ -104,7 +104,7 @@ lpc_device_parse(const char *opts)
 			if (romfile == NULL) {
 				errx(4, "invalid bootrom option \"%s\"", opts);
 			}
-			set_config_value("lpc.bootrom", romfile);
+			set_config_value("bootrom", romfile);
 
 			varfile = strsep(&str, ",");
 			if (varfile == NULL) {
@@ -112,7 +112,7 @@ lpc_device_parse(const char *opts)
 				goto done;
 			}
 			if (strchr(varfile, '=') == NULL) {
-				set_config_value("lpc.bootvars", varfile);
+				set_config_value("bootvars", varfile);
 			} else {
 				/* varfile doesn't exist, it's another config
 				 * option */
@@ -182,13 +182,6 @@ lpc_print_supported_devices(void)
 	printf("%s\n", pctestdev_getname());
 }
 
-const char *
-lpc_bootrom(void)
-{
-
-	return (get_config_value("lpc.bootrom"));
-}
-
 const char *
 lpc_fwcfg(void)
 {
@@ -256,14 +249,6 @@ lpc_init(struct vmctx *ctx)
 	const char *backend, *name;
 	char *node_name;
 	int unit, error;
-	const nvlist_t *nvl;
-
-	nvl = find_config_node("lpc");
-	if (nvl != NULL && nvlist_exists(nvl, "bootrom")) {
-		error = bootrom_loadrom(ctx, nvl);
-		if (error)
-			return (error);
-	}
 
 	/* COM1 and COM2 */
 	for (unit = 0; unit < LPC_UART_NUM; unit++) {
diff --git a/usr.sbin/bhyve/amd64/pci_lpc.h b/usr.sbin/bhyve/amd64/pci_lpc.h
index 2dca8f7bec24..402eae082545 100644
--- a/usr.sbin/bhyve/amd64/pci_lpc.h
+++ b/usr.sbin/bhyve/amd64/pci_lpc.h
@@ -69,7 +69,6 @@ int	lpc_device_parse(const char *opt);
 void    lpc_print_supported_devices(void);
 char	*lpc_pirq_name(int pin);
 void	lpc_pirq_routed(void);
-const char *lpc_bootrom(void);
 const char *lpc_fwcfg(void);
 
 #endif
diff --git a/usr.sbin/bhyve/bhyve_config.5 b/usr.sbin/bhyve/bhyve_config.5
index d0e5c8ae47d3..25185e2ef1b4 100644
--- a/usr.sbin/bhyve/bhyve_config.5
+++ b/usr.sbin/bhyve/bhyve_config.5
@@ -23,7 +23,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd November 20, 2023
+.Dd August 13, 2024
 .Dt BHYVE_CONFIG 5
 .Os
 .Sh NAME
@@ -120,6 +120,17 @@ The value must be formatted as described in
 .Xr expand_number 3 .
 .It Va memory.wired Ta bool Ta false Ta
 Wire guest memory.
+.It Va bootrom Ta path Ta Ta
+Path to a boot ROM.
+During initialization of the guest, the contents of this file are copied into
+the guest's memory.
+If a boot ROM is present, a firmware interface device is
+also enabled for use by the boot ROM.
+.It Va bootvars Ta path Ta Ta
+Path to boot VARS.
+The contents of this file are copied beneath the boot ROM.
+Firmware can write to it to save variables.
+All variables will be persistent even on reboots of the guest.
 .It Va acpi_tables Ta bool Ta true Ta
 Generate ACPI tables.
 .It Va acpi_tables_in_memory Ta bool Ta true Ta
@@ -146,6 +157,9 @@ Specify the keyboard layout name with the file name in
 This value only works when loaded with UEFI mode for VNC, and
 used a VNC client that don't support QEMU Extended Key Event
 Message (e.g. TightVNC).
+.It Va pci.enable_bars Ta bool Ta Ta
+Enable and map PCI BARs before executing any guest code.
+This setting is false by default when using a boot ROM and true otherwise.
 .It Va tpm.path Ta string Ta Ta
 Path to the host TPM device.
 This is typically /dev/tpm0.
@@ -550,17 +564,6 @@ The following nodes are available under
 .Va lpc :
 .Bl -column "pc-testdev" "Format" "Default"
 .It Sy Name Ta Sy Format Ta Sy Default Ta Sy Description
-.It Va bootrom Ta path Ta Ta
-Path to a boot ROM.
-The contents of this file are copied into the guest's
-memory ending just before the 4GB physical address.
-If a boot ROM is present, a firmware interface device is
-also enabled for use by the boot ROM.
-.It Va bootvars Ta path Ta Ta
-Path to boot VARS.
-The contents of this file are copied beneath the boot ROM.
-Firmware can write to it to save variables.
-All variables will be persistent even on reboots of the guest.
 .It Va com1 Ta node Ta Ta
 Settings for the COM1 serial port device.
 .It Va com2 Ta node Ta Ta
diff --git a/usr.sbin/bhyve/bhyverun.c b/usr.sbin/bhyve/bhyverun.c
index aca770a92642..41655a188bf9 100644
--- a/usr.sbin/bhyve/bhyverun.c
+++ b/usr.sbin/bhyve/bhyverun.c
@@ -413,7 +413,8 @@ fbsdrun_addcpu(int vcpuid)
 
 	CPU_SET_ATOMIC(vcpuid, &cpumask);
 
-	vm_suspend_cpu(vi->vcpu);
+	error = vm_suspend_cpu(vi->vcpu);
+	assert(error == 0);
 
 	error = pthread_create(&thr, NULL, fbsdrun_start_thread, vi);
 	assert(error == 0);
@@ -524,12 +525,7 @@ do_open(const char *vmname)
 
 	reinit = false;
 
-#ifdef __amd64__
-	romboot = lpc_bootrom() != NULL;
-#else
-	romboot = true;
-#endif
-
+	romboot = bootrom_boot();
 	error = vm_create(vmname);
 	if (error) {
 		if (errno == EEXIST) {
diff --git a/usr.sbin/bhyve/bootrom.c b/usr.sbin/bhyve/bootrom.c
index 1d461ba76597..e4adaca55947 100644
--- a/usr.sbin/bhyve/bootrom.c
+++ b/usr.sbin/bhyve/bootrom.c
@@ -192,7 +192,7 @@ bootrom_alloc(struct vmctx *ctx, size_t len, int prot, int flags,
 }
 
 int
-bootrom_loadrom(struct vmctx *ctx, const nvlist_t *nvl)
+bootrom_loadrom(struct vmctx *ctx)
 {
 	struct stat sbuf;
 	ssize_t rlen;
@@ -204,9 +204,9 @@ bootrom_loadrom(struct vmctx *ctx, const nvlist_t *nvl)
 	rv = -1;
 	varfd = -1;
 
-	bootrom = get_config_value_node(nvl, "bootrom");
+	bootrom = get_config_value("bootrom");
 	if (bootrom == NULL) {
-		return (-1);
+		return (0);
 	}
 
 	/*
@@ -235,7 +235,7 @@ bootrom_loadrom(struct vmctx *ctx, const nvlist_t *nvl)
 
 	rom_size = sbuf.st_size;
 
-	varfile = get_config_value_node(nvl, "bootvars");
+	varfile = get_config_value("bootvars");
 	var_size = 0;
 	if (varfile != NULL) {
 		varfd = open(varfile, O_RDWR);
@@ -314,3 +314,12 @@ bootrom_loadrom(struct vmctx *ctx, const nvlist_t *nvl)
 	free(romfile);
 	return (rv);
 }
+
+/*
+ * Are we relying on a bootrom to initialize the guest's CPU context?
+ */
+bool
+bootrom_boot(void)
+{
+	return (get_config_value("bootrom") != NULL);
+}
diff --git a/usr.sbin/bhyve/bootrom.h b/usr.sbin/bhyve/bootrom.h
index d22ac3718fa2..0477b0f35218 100644
--- a/usr.sbin/bhyve/bootrom.h
+++ b/usr.sbin/bhyve/bootrom.h
@@ -45,6 +45,7 @@ enum {
 };
 int bootrom_alloc(struct vmctx *ctx, size_t len, int prot, int flags,
     char **region_out, uint64_t *gpa_out);
-int bootrom_loadrom(struct vmctx *ctx, const nvlist_t *nvl);
+bool bootrom_boot(void);
+int bootrom_loadrom(struct vmctx *ctx);
 
 #endif
diff --git a/usr.sbin/bhyve/gdb.c b/usr.sbin/bhyve/gdb.c
index c62b0278b4e1..18cd17624924 100644
--- a/usr.sbin/bhyve/gdb.c
+++ b/usr.sbin/bhyve/gdb.c
@@ -696,6 +696,28 @@ append_packet_data(const uint8_t *data, size_t len)
 	}
 }
 
+static void
+append_binary_data(const uint8_t *data, size_t len)
+{
+	uint8_t buf[2];
+
+	for (; len > 0; data++, len--) {
+		switch (*data) {
+		case '}':
+		case '#':
+		case '$':
+		case '*':
+			buf[0] = 0x7d;
+			buf[1] = *data ^ 0x20;
+			append_packet_data(buf, 2);
+			break;
+		default:
+			append_packet_data(data, 1);
+			break;
+		}
+	}
+}
+
 static void
 append_string(const char *str)
 {
@@ -975,8 +997,28 @@ gdb_cpu_add(struct vcpu *vcpu)
 	 * executing the first instruction.
 	 */
 	if (!CPU_EMPTY(&vcpus_suspended)) {
+		cpuset_t suspended;
+		int error;
+
+		error = vm_debug_cpus(ctx, &suspended);
+		assert(error == 0);
+
 		CPU_SET(vcpuid, &vcpus_suspended);
 		_gdb_cpu_suspend(vcpu, false);
+
+		/*
+		 * In general, APs are started in a suspended mode such that
+		 * they exit with VM_EXITCODE_DEBUG until the BSP starts them.
+		 * In particular, this refers to the kernel's view of the vCPU
+		 * state rather than our own.  If the debugger resumes guest
+		 * execution, vCPUs will be unsuspended from the kernel's point
+		 * of view, so we should restore the previous state before
+		 * continuing.
+		 */
+		if (CPU_ISSET(vcpuid, &suspended)) {
+			error = vm_suspend_cpu(vcpu);
+			assert(error == 0);
+		}
 	}
 	pthread_mutex_unlock(&gdb_lock);
 }
@@ -1867,10 +1909,10 @@ gdb_query(const uint8_t *data, size_t len)
 			append_char('l');
 		} else if (doff + dlen >= xmllen) {
 			append_char('l');
-			append_packet_data(xml + doff, xmllen - doff);
+			append_binary_data(xml + doff, xmllen - doff);
 		} else {
 			append_char('m');
-			append_packet_data(xml + doff, dlen);
+			append_binary_data(xml + doff, dlen);
 		}
 		finish_packet();
 		(void)munmap(__DECONST(void *, xml), xmllen);
@@ -1934,11 +1976,11 @@ gdb_query(const uint8_t *data, size_t len)
 			append_char('l');
 		} else if (doff + dlen >= sizeof(capbuf)) {
 			append_char('l');
-			append_packet_data(capbuf + doff,
+			append_binary_data(capbuf + doff,
 			    sizeof(capbuf) - doff);
 		} else {
 			append_char('m');
-			append_packet_data(capbuf + doff, dlen);
+			append_binary_data(capbuf + doff, dlen);
 		}
 		finish_packet();
 #else
diff --git a/usr.sbin/bhyve/pci_emul.c b/usr.sbin/bhyve/pci_emul.c
index 00e9138d3910..b61f29aa6830 100644
--- a/usr.sbin/bhyve/pci_emul.c
+++ b/usr.sbin/bhyve/pci_emul.c
@@ -48,6 +48,7 @@
 
 #include "acpi.h"
 #include "bhyverun.h"
+#include "bootrom.h"
 #include "config.h"
 #include "debug.h"
 #ifdef __amd64__
@@ -853,6 +854,14 @@ pci_emul_alloc_bar(struct pci_devinst *pdi, int idx, enum pcibar_type type,
 		TAILQ_INSERT_BEFORE(bar, new_bar, chain);
 	}
 
+	/*
+	 * Enable PCI BARs only if we don't have a boot ROM, i.e., bhyveload was
+	 * used to load the initial guest image.  Otherwise, we rely on the boot
+	 * ROM to handle this.
+	 */
+	if (!get_config_bool_default("pci.enable_bars", !bootrom_boot()))
+		return (0);
+
 	/*
 	 * pci_passthru devices synchronize their physical and virtual command
 	 * register on init. For that reason, the virtual cmd reg should be
@@ -966,8 +975,19 @@ pci_emul_assign_bar(struct pci_devinst *const pdi, const int idx,
 		pci_set_cfgdata32(pdi, PCIR_BAR(idx + 1), bar >> 32);
 	}
 
-	if (type != PCIBAR_ROM) {
-		register_bar(pdi, idx);
+	switch (type) {
+	case PCIBAR_IO:
+		if (porten(pdi))
+			register_bar(pdi, idx);
+		break;
+	case PCIBAR_MEM32:
+	case PCIBAR_MEM64:
+	case PCIBAR_MEMHI64:
+		if (memen(pdi))
+			register_bar(pdi, idx);
+		break;
+	default:
+		break;
 	}
 
 	return (0);
@@ -1140,7 +1160,8 @@ pci_emul_init(struct vmctx *ctx, struct pci_devemu *pde, int bus, int slot,
 	pci_set_cfgdata8(pdi, PCIR_INTLINE, 255);
 	pci_set_cfgdata8(pdi, PCIR_INTPIN, 0);
 
-	pci_set_cfgdata8(pdi, PCIR_COMMAND, PCIM_CMD_BUSMASTEREN);
+	if (get_config_bool_default("pci.enable_bars", !bootrom_boot()))
+		pci_set_cfgdata8(pdi, PCIR_COMMAND, PCIM_CMD_BUSMASTEREN);
 
 	err = (*pde->pe_init)(pdi, fi->fi_config);
 	if (err == 0)