diff --git a/deps/openssl/openssl-cl_asm.gypi b/deps/openssl/openssl-cl_asm.gypi
index 8791e005bf0f41..cd10355c171228 100644
--- a/deps/openssl/openssl-cl_asm.gypi
+++ b/deps/openssl/openssl-cl_asm.gypi
@@ -1,6 +1,6 @@
 {
   'conditions': [
-    ['target_arch=="ppc64" and OS=="aix"', {
+    ['target_arch=="ppc64" and OS in ("aix", "os400")', {
       'includes': ['config/archs/aix64-gcc-as/asm/openssl-cl.gypi'],
     }, 'target_arch=="ppc64" and OS=="linux" and node_byteorder =="little"', {
       'includes': ['config/archs/linux-ppc64le/asm/openssl-cl.gypi'],
diff --git a/deps/openssl/openssl-cl_asm_avx2.gypi b/deps/openssl/openssl-cl_asm_avx2.gypi
index 815598676770c6..50b5a9c375bd8d 100644
--- a/deps/openssl/openssl-cl_asm_avx2.gypi
+++ b/deps/openssl/openssl-cl_asm_avx2.gypi
@@ -1,6 +1,6 @@
 {
   'conditions': [
-    ['target_arch=="ppc64" and OS=="aix"', {
+    ['target_arch=="ppc64" and OS in ("aix", "os400")', {
       'includes': ['config/archs/aix64-gcc-as/asm_avx2/openssl-cl.gypi'],
     }, 'target_arch=="ppc64" and OS=="linux" and node_byteorder =="little"', {
       'includes': ['config/archs/linux-ppc64le/asm_avx2/openssl-cl.gypi'],
diff --git a/deps/openssl/openssl-cl_no_asm.gypi b/deps/openssl/openssl-cl_no_asm.gypi
index 22bcf1c3c77d84..0964fb36739b3a 100644
--- a/deps/openssl/openssl-cl_no_asm.gypi
+++ b/deps/openssl/openssl-cl_no_asm.gypi
@@ -1,6 +1,6 @@
 {
   'conditions': [
-    ['target_arch=="ppc64" and OS=="aix"', {
+    ['target_arch=="ppc64" and OS in ("aix", "os400")', {
       'includes': ['config/archs/aix64-gcc-as/no-asm/openssl-cl.gypi'],
     }, 'target_arch=="ppc64" and OS=="linux" and node_byteorder =="little"', {
       'includes': ['config/archs/linux-ppc64le/no-asm/openssl-cl.gypi'],
diff --git a/deps/openssl/openssl-fips_asm.gypi b/deps/openssl/openssl-fips_asm.gypi
index d0717df2a5094f..631df9eb893288 100644
--- a/deps/openssl/openssl-fips_asm.gypi
+++ b/deps/openssl/openssl-fips_asm.gypi
@@ -1,6 +1,6 @@
 {
   'conditions': [
-    ['target_arch=="ppc64" and OS=="aix"', {
+    ['target_arch=="ppc64" and OS in ("aix", "os400")', {
       'includes': ['config/archs/aix64-gcc-as/asm/openssl-fips.gypi'],
     }, 'target_arch=="ppc64" and OS=="linux" and node_byteorder =="little"', {
       'includes': ['config/archs/linux-ppc64le/asm/openssl-fips.gypi'],
diff --git a/deps/openssl/openssl-fips_asm_avx2.gypi b/deps/openssl/openssl-fips_asm_avx2.gypi
index d2a2a4bc11413f..4d63cacf29d040 100644
--- a/deps/openssl/openssl-fips_asm_avx2.gypi
+++ b/deps/openssl/openssl-fips_asm_avx2.gypi
@@ -1,6 +1,6 @@
 {
   'conditions': [
-    ['target_arch=="ppc64" and OS=="aix"', {
+    ['target_arch=="ppc64" and OS in ("aix", "os400")', {
       'includes': ['config/archs/aix64-gcc-as/asm_avx2/openssl-fips.gypi'],
     }, 'target_arch=="ppc64" and OS=="linux" and node_byteorder =="little"', {
       'includes': ['config/archs/linux-ppc64le/asm_avx2/openssl-fips.gypi'],
diff --git a/deps/openssl/openssl-fips_no_asm.gypi b/deps/openssl/openssl-fips_no_asm.gypi
index d598bde68c783d..7fdfd772abbce8 100644
--- a/deps/openssl/openssl-fips_no_asm.gypi
+++ b/deps/openssl/openssl-fips_no_asm.gypi
@@ -1,7 +1,7 @@
 {
   'defines': ['OPENSSL_NO_ASM'],
   'conditions': [
-    ['target_arch=="ppc64" and OS=="aix"', {
+    ['target_arch=="ppc64" and OS in ("aix", "os400")', {
       'includes': ['config/archs/aix64-gcc-as/no-asm/openssl-fips.gypi'],
     }, 'target_arch=="ppc64" and OS=="linux" and node_byteorder =="little"', {
       'includes': ['config/archs/linux-ppc64le/no-asm/openssl-fips.gypi'],
diff --git a/deps/openssl/openssl_asm.gypi b/deps/openssl/openssl_asm.gypi
index dbd5a5f69ff8d9..dd7e636eb08893 100644
--- a/deps/openssl/openssl_asm.gypi
+++ b/deps/openssl/openssl_asm.gypi
@@ -1,6 +1,6 @@
 {
   'conditions': [
-    ['target_arch=="ppc64" and OS=="aix"', {
+    ['target_arch=="ppc64" and OS in ("aix", "os400")', {
       'includes': ['config/archs/aix64-gcc-as/asm/openssl.gypi'],
     }, 'target_arch=="ppc64" and OS=="linux" and node_byteorder =="little"', {
       'includes': ['config/archs/linux-ppc64le/asm/openssl.gypi'],
diff --git a/deps/openssl/openssl_asm_avx2.gypi b/deps/openssl/openssl_asm_avx2.gypi
index 2883f83d694394..6a9c56d76a211a 100644
--- a/deps/openssl/openssl_asm_avx2.gypi
+++ b/deps/openssl/openssl_asm_avx2.gypi
@@ -1,6 +1,6 @@
 {
   'conditions': [
-    ['target_arch=="ppc64" and OS=="aix"', {
+    ['target_arch=="ppc64" and OS in ("aix", "os400")', {
       'includes': ['config/archs/aix64-gcc-as/asm_avx2/openssl.gypi'],
     }, 'target_arch=="ppc64" and OS=="linux" and node_byteorder =="little"', {
       'includes': ['config/archs/linux-ppc64le/asm_avx2/openssl.gypi'],
diff --git a/deps/openssl/openssl_common.gypi b/deps/openssl/openssl_common.gypi
index 256eb7d1808db3..1290fff251fc5b 100644
--- a/deps/openssl/openssl_common.gypi
+++ b/deps/openssl/openssl_common.gypi
@@ -13,7 +13,7 @@
   ],
   # build options specific to OS
   'conditions': [
-    [ 'OS=="aix"', {
+    [ 'OS in ("aix", "os400")', {
       # AIX is missing /usr/include/endian.h
       'defines': [
         '__LITTLE_ENDIAN=1234',
diff --git a/deps/openssl/openssl_no_asm.gypi b/deps/openssl/openssl_no_asm.gypi
index de0e486f67e90e..20663decabba23 100644
--- a/deps/openssl/openssl_no_asm.gypi
+++ b/deps/openssl/openssl_no_asm.gypi
@@ -1,7 +1,7 @@
 {
   'defines': ['OPENSSL_NO_ASM'],
   'conditions': [
-    ['target_arch=="ppc64" and OS=="aix"', {
+    ['target_arch=="ppc64" and OS in ("aix", "os400")', {
       'includes': ['config/archs/aix64-gcc-as/no-asm/openssl.gypi'],
     }, 'target_arch=="ppc64" and OS=="linux" and node_byteorder =="little"', {
       'includes': ['config/archs/linux-ppc64le/no-asm/openssl.gypi'],
diff --git a/test/abort/test-addon-uv-handle-leak.js b/test/abort/test-addon-uv-handle-leak.js
index e494b12f2de558..d2c4f8e646f457 100644
--- a/test/abort/test-addon-uv-handle-leak.js
+++ b/test/abort/test-addon-uv-handle-leak.js
@@ -78,6 +78,7 @@ if (process.argv[2] === 'child') {
 
   if (!(common.isFreeBSD ||
         common.isAIX ||
+        common.isIBMi ||
         (common.isLinux && !isGlibc()) ||
         common.isWindows)) {
     assert(stderr.includes('ExampleOwnerClass'), stderr);
diff --git a/test/common/index.js b/test/common/index.js
index 338e773a353eff..dfce909f95cd13 100644
--- a/test/common/index.js
+++ b/test/common/index.js
@@ -123,7 +123,6 @@ if (process.argv.length === 2 &&
 }
 
 const isWindows = process.platform === 'win32';
-const isAIX = process.platform === 'aix';
 const isSunOS = process.platform === 'sunos';
 const isFreeBSD = process.platform === 'freebsd';
 const isOpenBSD = process.platform === 'openbsd';
@@ -274,7 +273,7 @@ function platformTimeout(ms) {
   if (process.features.debug)
     ms = multipliers.two * ms;
 
-  if (isAIX)
+  if (exports.isAIX || exports.isIBMi)
     return multipliers.two * ms; // Default localhost speed is slower on AIX
 
   if (isPi)
@@ -925,7 +924,6 @@ const common = {
   hasQuic,
   hasMultiLocalhost,
   invalidArgTypeHelper,
-  isAIX,
   isAlive,
   isAsan,
   isDumbTerminal,
@@ -996,7 +994,12 @@ const common = {
   },
 
   // On IBMi, process.platform and os.platform() both return 'aix',
+  // when built with Python versions earlier than 3.9.
   // It is not enough to differentiate between IBMi and real AIX system.
+  get isAIX() {
+    return require('os').type() === 'AIX';
+  },
+
   get isIBMi() {
     return require('os').type() === 'OS400';
   },
diff --git a/test/known_issues/test-cwd-enoent-file.js b/test/known_issues/test-cwd-enoent-file.js
index 0f75896134f7e3..6d99987895baf4 100644
--- a/test/known_issues/test-cwd-enoent-file.js
+++ b/test/known_issues/test-cwd-enoent-file.js
@@ -5,7 +5,7 @@
 const common = require('../common');
 const assert = require('assert');
 
-if (common.isSunOS || common.isWindows || common.isAIX) {
+if (common.isSunOS || common.isWindows || common.isAIX || common.isIBMi) {
   // The current working directory cannot be removed on these platforms.
   // Change this to common.skip() when this is no longer a known issue test.
   assert.fail('cannot rmdir current working directory');
diff --git a/test/parallel/test-cwd-enoent-preload.js b/test/parallel/test-cwd-enoent-preload.js
index 2077d9c1478335..21b20d6d035672 100644
--- a/test/parallel/test-cwd-enoent-preload.js
+++ b/test/parallel/test-cwd-enoent-preload.js
@@ -1,7 +1,7 @@
 'use strict';
 const common = require('../common');
 // Fails with EINVAL on SmartOS, EBUSY on Windows, EBUSY on AIX.
-if (common.isSunOS || common.isWindows || common.isAIX)
+if (common.isSunOS || common.isWindows || common.isAIX || common.isIBMi)
   common.skip('cannot rmdir current working directory');
 if (!common.isMainThread)
   common.skip('process.chdir is not available in Workers');
diff --git a/test/parallel/test-cwd-enoent-repl.js b/test/parallel/test-cwd-enoent-repl.js
index 5ea8abc7e42b52..0a61cbfbced9b4 100644
--- a/test/parallel/test-cwd-enoent-repl.js
+++ b/test/parallel/test-cwd-enoent-repl.js
@@ -1,7 +1,7 @@
 'use strict';
 const common = require('../common');
 // Fails with EINVAL on SmartOS, EBUSY on Windows, EBUSY on AIX.
-if (common.isSunOS || common.isWindows || common.isAIX)
+if (common.isSunOS || common.isWindows || common.isAIX || common.isIBMi)
   common.skip('cannot rmdir current working directory');
 if (!common.isMainThread)
   common.skip('process.chdir is not available in Workers');
diff --git a/test/parallel/test-cwd-enoent.js b/test/parallel/test-cwd-enoent.js
index 8beb1e3fbe0a05..876888bc2be518 100644
--- a/test/parallel/test-cwd-enoent.js
+++ b/test/parallel/test-cwd-enoent.js
@@ -1,7 +1,7 @@
 'use strict';
 const common = require('../common');
 // Fails with EINVAL on SmartOS, EBUSY on Windows, EBUSY on AIX.
-if (common.isSunOS || common.isWindows || common.isAIX)
+if (common.isSunOS || common.isWindows || common.isAIX || common.isIBMi)
   common.skip('cannot rmdir current working directory');
 if (!common.isMainThread)
   common.skip('process.chdir is not available in Workers');
diff --git a/test/parallel/test-fs-readfile-pipe-large.js b/test/parallel/test-fs-readfile-pipe-large.js
index 1a685ebc612b85..4376774bb411d6 100644
--- a/test/parallel/test-fs-readfile-pipe-large.js
+++ b/test/parallel/test-fs-readfile-pipe-large.js
@@ -3,7 +3,7 @@ const common = require('../common');
 
 // Simulate `cat readfile.js | node readfile.js`
 
-if (common.isWindows || common.isAIX)
+if (common.isWindows || common.isAIX || common.isIBMi)
   common.skip(`No /dev/stdin on ${process.platform}.`);
 
 const assert = require('assert');
diff --git a/test/parallel/test-fs-readfile-pipe.js b/test/parallel/test-fs-readfile-pipe.js
index 0cffbd0f5aa162..79d5699fef64a4 100644
--- a/test/parallel/test-fs-readfile-pipe.js
+++ b/test/parallel/test-fs-readfile-pipe.js
@@ -24,7 +24,7 @@ const common = require('../common');
 
 // Simulate `cat readfile.js | node readfile.js`
 
-if (common.isWindows || common.isAIX)
+if (common.isWindows || common.isAIX || common.isIBMi)
   common.skip(`No /dev/stdin on ${process.platform}.`);
 
 const assert = require('assert');
diff --git a/test/parallel/test-fs-readfilesync-pipe-large.js b/test/parallel/test-fs-readfilesync-pipe-large.js
index 2cb857a329fbee..5450337c4f680a 100644
--- a/test/parallel/test-fs-readfilesync-pipe-large.js
+++ b/test/parallel/test-fs-readfilesync-pipe-large.js
@@ -3,7 +3,7 @@ const common = require('../common');
 
 // Simulate `cat readfile.js | node readfile.js`
 
-if (common.isWindows || common.isAIX)
+if (common.isWindows || common.isAIX || common.isIBMi)
   common.skip(`No /dev/stdin on ${process.platform}.`);
 
 const assert = require('assert');
diff --git a/test/parallel/test-fs-realpath-pipe.js b/test/parallel/test-fs-realpath-pipe.js
index 29fe1d3b7d28e1..f637642ca21d67 100644
--- a/test/parallel/test-fs-realpath-pipe.js
+++ b/test/parallel/test-fs-realpath-pipe.js
@@ -2,7 +2,7 @@
 
 const common = require('../common');
 
-if (common.isWindows || common.isAIX)
+if (common.isWindows || common.isAIX || common.isIBMi)
   common.skip(`No /dev/stdin on ${process.platform}.`);
 
 const assert = require('assert');
diff --git a/test/parallel/test-fs-utimes.js b/test/parallel/test-fs-utimes.js
index 8f8286f8a3343f..e6ae75d4e33a5f 100644
--- a/test/parallel/test-fs-utimes.js
+++ b/test/parallel/test-fs-utimes.js
@@ -39,7 +39,7 @@ function stat_resource(resource, statSync = fs.statSync) {
   const stats = fs.fstatSync(resource);
   // Ensure mtime has been written to disk
   // except for directories on AIX where it cannot be synced
-  if (common.isAIX && stats.isDirectory())
+  if ((common.isAIX || common.isIBMi) && stats.isDirectory())
     return stats;
   fs.fsyncSync(resource);
   return fs.fstatSync(resource);
diff --git a/test/parallel/test-os.js b/test/parallel/test-os.js
index d82f2ece3159a6..f7059260ce507e 100644
--- a/test/parallel/test-os.js
+++ b/test/parallel/test-os.js
@@ -81,11 +81,14 @@ const hostname = os.hostname();
 is.string(hostname);
 assert.ok(hostname.length > 0);
 
-const DUMMY_PRIORITY = 10;
-os.setPriority(DUMMY_PRIORITY);
-const priority = os.getPriority();
-is.number(priority);
-assert.strictEqual(priority, DUMMY_PRIORITY);
+// IBMi process priority is different.
+if (!common.isIBMi) {
+  const DUMMY_PRIORITY = 10;
+  os.setPriority(DUMMY_PRIORITY);
+  const priority = os.getPriority();
+  is.number(priority);
+  assert.strictEqual(priority, DUMMY_PRIORITY);
+}
 
 // On IBMi, os.uptime() returns 'undefined'
 if (!common.isIBMi) {
diff --git a/test/parallel/test-process-dlopen-error-message-crash.js b/test/parallel/test-process-dlopen-error-message-crash.js
index d678021764e8f4..de8b3033195a46 100644
--- a/test/parallel/test-process-dlopen-error-message-crash.js
+++ b/test/parallel/test-process-dlopen-error-message-crash.js
@@ -17,7 +17,7 @@ assert.throws(() => {
 }, ({ name, code, message }) => {
   assert.strictEqual(name, 'Error');
   assert.strictEqual(code, 'ERR_DLOPEN_FAILED');
-  if (!common.isAIX) {
+  if (!common.isAIX && !common.isIBMi) {
     assert.match(message, /foo-%s\.node/);
   }
   return true;