diff --git a/app/forms/image-upload.tsx b/app/forms/image-upload.tsx
index fca839ef2f..f16d67b4f4 100644
--- a/app/forms/image-upload.tsx
+++ b/app/forms/image-upload.tsx
@@ -44,6 +44,7 @@ import { readBlobAsBase64 } from '~/util/file'
 import { invariant } from '~/util/invariant'
 import { links } from '~/util/links'
 import { pb } from '~/util/path-builder'
+import { isAllZeros } from '~/util/str'
 import { GiB, KiB } from '~/util/units'
 
 /** Format file size with two decimal points */
@@ -113,12 +114,6 @@ function Step({ children, state, label, className }: StepProps) {
   )
 }
 
-/**
- * Does a base64 string represent underlying data that's all zeros, i.e., does
- * it look like `AAAAAAAAAAAAAAAA==`?
- */
-export const isAllZeros = (base64Data: string) => /^A*=*$/.test(base64Data)
-
 const randInt = () => Math.floor(Math.random() * 100000000)
 
 function getTmpDiskName(imageName: string) {
diff --git a/app/ui/lib/Modal.tsx b/app/ui/lib/Modal.tsx
index 4632fcbccc..8e61d0f613 100644
--- a/app/ui/lib/Modal.tsx
+++ b/app/ui/lib/Modal.tsx
@@ -7,7 +7,7 @@
  */
 import * as Dialog from '@radix-ui/react-dialog'
 import { animated, useTransition } from '@react-spring/web'
-import React, { createContext, forwardRef, useContext, useId } from 'react'
+import React, { forwardRef, useId } from 'react'
 
 import { Close12Icon } from '@oxide/design-system/icons/react'
 
@@ -15,10 +15,7 @@ import { classed } from '~/util/classed'
 
 import { Button } from './Button'
 import { DialogOverlay } from './DialogOverlay'
-
-const ModalContext = createContext(false)
-
-export const useIsInModal = () => useContext(ModalContext)
+import { ModalContext } from './modal-context'
 
 export type ModalProps = {
   title?: string
diff --git a/app/ui/lib/SideModal.tsx b/app/ui/lib/SideModal.tsx
index f1404a4a4b..9f461aad97 100644
--- a/app/ui/lib/SideModal.tsx
+++ b/app/ui/lib/SideModal.tsx
@@ -8,20 +8,16 @@
 import * as Dialog from '@radix-ui/react-dialog'
 import { animated, useTransition } from '@react-spring/web'
 import cn from 'classnames'
-import React, { createContext, useContext, useRef, type ReactNode } from 'react'
+import React, { useRef, type ReactNode } from 'react'
 
 import { Close12Icon, Error12Icon } from '@oxide/design-system/icons/react'
 
 import { useIsOverflow } from '~/hooks'
 import { Message } from '~/ui/lib/Message'
-import { useIsInModal } from '~/ui/lib/Modal'
 import { classed } from '~/util/classed'
 
 import { DialogOverlay } from './DialogOverlay'
-
-const SideModalContext = createContext(false)
-
-export const useIsInSideModal = () => useContext(SideModalContext)
+import { SideModalContext, useIsInModal, useIsInSideModal } from './modal-context'
 
 export function usePopoverZIndex() {
   const isInModal = useIsInModal()
diff --git a/app/ui/lib/modal-context.ts b/app/ui/lib/modal-context.ts
new file mode 100644
index 0000000000..54ac677632
--- /dev/null
+++ b/app/ui/lib/modal-context.ts
@@ -0,0 +1,15 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, you can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * Copyright Oxide Computer Company
+ */
+
+import { createContext, useContext } from 'react'
+
+export const ModalContext = createContext(false)
+export const useIsInModal = () => useContext(ModalContext)
+
+export const SideModalContext = createContext(false)
+export const useIsInSideModal = () => useContext(SideModalContext)
diff --git a/app/forms/all-zeros.spec.ts b/app/util/all-zeros.spec.ts
similarity index 96%
rename from app/forms/all-zeros.spec.ts
rename to app/util/all-zeros.spec.ts
index 0ffb361820..43c2915104 100644
--- a/app/forms/all-zeros.spec.ts
+++ b/app/util/all-zeros.spec.ts
@@ -7,7 +7,7 @@
  */
 import { expect, test } from 'vitest'
 
-import { isAllZeros } from './image-upload'
+import { isAllZeros } from '~/util/str'
 
 function numberToUint8Array(num: number) {
   const bytes = []
diff --git a/app/util/str.ts b/app/util/str.ts
index 55cde1f7bb..069f8508ee 100644
--- a/app/util/str.ts
+++ b/app/util/str.ts
@@ -65,3 +65,9 @@ export const validateIp = (ip: string) => {
   const isv6 = !isv4 && IPV6_REGEX.test(ip)
   return { isv4, isv6, valid: isv4 || isv6 }
 }
+
+/**
+ * Does a base64 string represent underlying data that's all zeros, i.e., does
+ * it look like `AAAAAAAAAAAAAAAA==`?
+ */
+export const isAllZeros = (base64Data: string) => /^A*=*$/.test(base64Data)