diff --git a/gui/app/src/components/commons/Dropdown.tsx b/gui/app/src/components/commons/Dropdown.tsx
index e1014451d2..6006e156d2 100644
--- a/gui/app/src/components/commons/Dropdown.tsx
+++ b/gui/app/src/components/commons/Dropdown.tsx
@@ -288,7 +288,7 @@ export function DropdownInside({
     <>
       <div
         className={classNames(
-          'min-h-[42px] text-background-10 text-left dropdown',
+          'min-h-[42px] min-w-0 text-background-10 text-left dropdown',
           displayStyles[display]
         )}
         onClick={() => setIsOpen(!isOpen)}
@@ -361,7 +361,7 @@ export function DropdownInside({
       >
         <div
           className={classNames(
-            'flex flex-row justify-between items-center gap-2 pl-3 pr-5 py-3 rounded-md cursor-pointer focus:ring-4 relative',
+            'flex flex-row justify-between items-center gap-2 pl-3 pr-5 py-3 rounded-md cursor-pointer focus:ring-4 relative min-w-0',
             variantStyles[variant]
           )}
           tabIndex={0}
@@ -374,8 +374,8 @@ export function DropdownInside({
           }
           role="combobox"
         >
-          {getShownValue(value)}
-          <div className="fill-background-10">
+          <span className="min-w-0 truncate">{getShownValue(value)}</span>
+          <div className="fill-background-10 shrink-0">
             {direction === 'up' ? (
               <ArrowUpIcon size={16} />
             ) : (
diff --git a/gui/app/src/components/firmware-tool/steps/BoardDefaultsStep.tsx b/gui/app/src/components/firmware-tool/steps/BoardDefaultsStep.tsx
index 4825dc390d..e246e8f565 100644
--- a/gui/app/src/components/firmware-tool/steps/BoardDefaultsStep.tsx
+++ b/gui/app/src/components/firmware-tool/steps/BoardDefaultsStep.tsx
@@ -21,15 +21,19 @@ function BoardDefaultsGraph({ graph }: { graph: ComponentNode[] }) {
   const renderComponent = (
     c: ComponentNode,
     depth = 0,
-    onDelete?: () => void
+    onDelete?: () => void,
+    layoutContext = { compactGroupChildren: false }
   ) => {
     if (c.type === 'group') {
+      const hasListChild = c.childrens.some((child) => child.type === 'list');
+
       return (
         <div
           key={c.path.join('/')}
           className={classNames('flex flex-col rounded-lg', {
             'p-4 ': depth !== 0,
             'bg-background-80': depth >= 1,
+            'sm:col-span-2': depth > 1 && c.layout?.spanTwoColumns,
           })}
         >
           <div className="flex justify-between items-center">
@@ -45,11 +49,21 @@ function BoardDefaultsGraph({ graph }: { graph: ComponentNode[] }) {
           </div>
           <div
             className={classNames({
-              'flex flex-col gap-4': depth + 1 <= 1,
-              'grid sm:grid-cols-2 gap-2 items-end': depth + 1 > 1,
+              'flex flex-col gap-4':
+                layoutContext.compactGroupChildren || depth + 1 <= 1,
+              'grid sm:grid-cols-2 gap-2 items-start':
+                !layoutContext.compactGroupChildren &&
+                depth + 1 > 1 &&
+                hasListChild,
+              'grid sm:grid-cols-2 gap-2 items-end':
+                !layoutContext.compactGroupChildren &&
+                depth + 1 > 1 &&
+                !hasListChild,
             })}
           >
-            {c.childrens.map((c) => renderComponent(c, depth + 1))}
+            {c.childrens.map((c) =>
+              renderComponent(c, depth + 1, undefined, layoutContext)
+            )}
           </div>
         </div>
       );
@@ -72,7 +86,7 @@ function BoardDefaultsGraph({ graph }: { graph: ComponentNode[] }) {
 
     if (c.type === 'text') {
       return (
-        <div className="flex flex-col pt-2" key={c.path.join('/')}>
+        <div className="flex flex-col pt-2 min-w-0" key={c.path.join('/')}>
           <InputInside
             name={c.label}
             label={c.label}
@@ -93,7 +107,10 @@ function BoardDefaultsGraph({ graph }: { graph: ComponentNode[] }) {
 
     if (c.type === 'dropdown') {
       return (
-        <div className="flex flex-col pt-2 gap-1" key={c.path.join('/')}>
+        <div
+          className="flex flex-col pt-2 gap-1 min-w-0"
+          key={c.path.join('/')}
+        >
           <Typography>{c.label}</Typography>
           <DropdownInside
             items={c.items.map((i) => ({ value: i, label: i }))}
@@ -115,25 +132,31 @@ function BoardDefaultsGraph({ graph }: { graph: ComponentNode[] }) {
     }
 
     if (c.type === 'list') {
+      const itemGridList = c.layout?.itemGridList ?? false;
+      const compactGroupChildren = c.layout?.compactGroupChildren ?? false;
+
       return (
         <div
           key={c.path.join('/')}
           className={classNames('flex flex-col gap-2 rounded-lg', {
             'p-4': depth >= 2,
             'bg-background-70': depth >= 1,
+            'sm:col-span-2': depth > 1 && c.layout?.spanTwoColumns,
           })}
         >
           <Typography variant="section-title">{c.label}</Typography>
           <div
             className={classNames({
-              'grid sm:grid-cols-2 gap-2': true,
+              'grid sm:grid-cols-2 gap-2': itemGridList,
+              'flex flex-col gap-2': !itemGridList,
             })}
           >
             {c.childrens.map((c2, index) =>
               renderComponent(
                 c2,
                 depth + 1,
-                c.del ? () => c.del?.(index) : undefined
+                c.del ? () => c.del?.(index) : undefined,
+                { compactGroupChildren }
               )
             )}
             {c.add && (
diff --git a/gui/app/src/hooks/firmware-tool.ts b/gui/app/src/hooks/firmware-tool.ts
index d27876ccc1..8154eeb2d7 100644
--- a/gui/app/src/hooks/firmware-tool.ts
+++ b/gui/app/src/hooks/firmware-tool.ts
@@ -184,6 +184,12 @@ type TraversalContext = {
   propertySchema?: SomeJSONSchema; // The original property schema (before ref resolution)
 };
 
+type ComponentLayout = {
+  itemGridList?: boolean;
+  compactGroupChildren?: boolean;
+  spanTwoColumns?: boolean;
+};
+
 export type ComponentNode =
   | {
       type: 'checkbox';
@@ -215,16 +221,46 @@ export type ComponentNode =
       label: string | undefined;
       childrens: ComponentNode[];
       path: Path;
+      layout?: ComponentLayout;
     }
   | {
       type: 'list';
       childrens: ComponentNode[];
       label: string;
       path: Path;
+      layout?: ComponentLayout;
       add?: () => void;
       del?: (index: number) => void;
     };
 
+const layoutForPath = (path: Path): ComponentLayout | undefined => {
+  const lastPathSegment = path[path.length - 1];
+
+  if (typeof lastPathSegment !== 'string') {
+    return undefined;
+  }
+
+  switch (lastPathSegment) {
+    case 'imus':
+      return {
+        itemGridList: true,
+        compactGroupChildren: true,
+        spanTwoColumns: true,
+      };
+    case 'sensors':
+      return {
+        itemGridList: true,
+        spanTwoColumns: true,
+      };
+    case 'buses':
+      return {
+        spanTwoColumns: true,
+      };
+  }
+
+  return undefined;
+};
+
 const setAtPath = (obj: any, path: Path, value: any): void => {
   let current = obj;
   for (let i = 0; i < path.length - 1; i++) {
@@ -340,6 +376,7 @@ const handleObjectNode = (
         childrens: childs,
         path: ctx.path,
         label: resolveLabel(ctx, node, ctx.propertySchema) ?? undefined,
+        layout: layoutForPath(ctx.path),
       },
     ];
   }
@@ -365,6 +402,25 @@ const handleDiscriminatedOneOf = (
   );
 
   const discriminatorPath = [...ctx.path, discriminator];
+
+  const getCandidate = (value: string): SomeJSONSchema | undefined => {
+    if (mapping[value]) {
+      return ctx.defs[refToKey(mapping[value])];
+    }
+
+    return node.oneOf!.find((o: SomeJSONSchema) => {
+      const target = o.$ref ? ctx.defs[refToKey(o.$ref)] : o;
+      const prop = target?.properties?.[discriminator];
+
+      if (!prop) return false;
+
+      if (prop.const === value) return true;
+      if (Array.isArray(prop.enum) && prop.enum.includes(value)) return true;
+
+      return false;
+    });
+  };
+
   const discriminatorDropdown: ComponentNode = {
     type: 'dropdown',
     label: discriminator,
@@ -372,8 +428,13 @@ const handleDiscriminatedOneOf = (
     value: discriminatorValue ?? possibleValues[0] ?? '',
     path: discriminatorPath,
     onMutate: (newValue: string) => {
-      setAtPath(ctx.rootData, discriminatorPath, newValue);
-      ctx.onChange(discriminatorPath, newValue, ctx.rootData);
+      const candidate = getCandidate(newValue);
+      const payload = candidate
+        ? createDefaultDataFromSchema(ctx, candidate)
+        : { [discriminator]: newValue };
+
+      setAtPath(ctx.rootData, ctx.path, payload);
+      ctx.onChange(ctx.path, payload, ctx.rootData);
     },
   };
 
@@ -384,26 +445,7 @@ const handleDiscriminatedOneOf = (
     return [];
   }
 
-  let candidate: SomeJSONSchema | undefined;
-
-  if (mapping[activeValue]) {
-    const mappedKey = refToKey(mapping[activeValue]);
-    candidate = ctx.defs[mappedKey];
-  }
-
-  if (!candidate) {
-    candidate = node.oneOf!.find((o: SomeJSONSchema) => {
-      const target = o.$ref ? ctx.defs[refToKey(o.$ref)] : o;
-      const prop = target?.properties?.[discriminator];
-
-      if (!prop) return false;
-
-      if (prop.const === activeValue) return true;
-      if (Array.isArray(prop.enum) && prop.enum.includes(activeValue)) return true;
-
-      return false;
-    });
-  }
+  const candidate = getCandidate(activeValue);
 
   if (!candidate) {
     console.warn(`No matching discriminator found for ${activeValue}, skipping`);
@@ -445,10 +487,95 @@ const handleDiscriminatedOneOf = (
         resolveLabel(ctx, resolvedCandidate) ??
         resolveLabel(ctx, node, ctx.propertySchema) ??
         undefined,
+      layout: layoutForPath(ctx.path),
     },
   ];
 };
 
+const cloneSchemaDefault = (node: SomeJSONSchema): any => {
+  const defaultValue = (node as { default?: unknown }).default;
+
+  if (defaultValue === undefined) {
+    return undefined;
+  }
+
+  if (defaultValue === null || typeof defaultValue !== 'object') {
+    return defaultValue;
+  }
+
+  return JSON.parse(JSON.stringify(defaultValue));
+};
+
+const createDefaultDataFromSchema = (
+  ctx: TraversalContext,
+  node: SomeJSONSchema
+): any => {
+  if (!ctx.defs) throw new Error('Board defaults schema is missing $defs');
+
+  if (node.$ref) {
+    return createDefaultDataFromSchema(ctx, ctx.defs[refToKey(node.$ref)]);
+  }
+
+  const schemaDefault = cloneSchemaDefault(node);
+  if (schemaDefault !== undefined) {
+    return schemaDefault;
+  }
+
+  if (node.const !== undefined) {
+    return node.const;
+  }
+
+  if (node.enum?.length) {
+    return node.enum[0];
+  }
+
+  if (node.oneOf && Array.isArray(node.oneOf) && node.discriminator?.propertyName) {
+    const discriminator = node.discriminator.propertyName;
+    const mapping = node.discriminator.mapping ?? {};
+    const discriminatorValue = extractDiscriminatorValues(
+      ctx,
+      node.oneOf,
+      discriminator,
+      mapping
+    )[0];
+    const mappedCandidate = discriminatorValue ? mapping[discriminatorValue] : null;
+    const candidate = mappedCandidate
+      ? ctx.defs[refToKey(mappedCandidate)]
+      : node.oneOf[0];
+
+    return candidate ? createDefaultDataFromSchema(ctx, candidate) : {};
+  }
+
+  if (node.type === 'object' && node.properties) {
+    const data: Record<string, any> = {};
+
+    for (const property of Object.keys(node.properties)) {
+      const propertySchema = node.properties[property];
+      if (propertySchema) {
+        data[property] = createDefaultDataFromSchema(ctx, propertySchema);
+      }
+    }
+
+    return data;
+  }
+
+  if (node.type === 'array') {
+    return Array.from({ length: node.minItems ?? 0 }, () =>
+      createDefaultDataFromSchema(ctx, node.items)
+    );
+  }
+
+  if (node.type === 'boolean') {
+    return false;
+  }
+
+  if (node.type === 'number') {
+    return 0;
+  }
+
+  return '';
+};
+
 const handleArrayNode = (
   ctx: TraversalContext,
   node: SomeJSONSchema
@@ -494,19 +621,24 @@ const handleArrayNode = (
         })
         .find((o: string) => !!o);
       if (discriminatorValue) {
-        const payload = {
-          [discriminator]: discriminatorValue,
-        };
+        const discriminatorCandidate = item.oneOf.find((o: SomeJSONSchema) => {
+          const target = o.$ref ? ctx.defs[refToKey(o.$ref)] : o;
+          return target?.properties?.[discriminator]?.const === discriminatorValue;
+        });
 
         add = () => {
+          const payload = discriminatorCandidate
+            ? createDefaultDataFromSchema(ctx, discriminatorCandidate)
+            : { [discriminator]: discriminatorValue };
           setAtPath(ctx.rootData, discriminatorPath, payload);
           ctx.onChange(discriminatorPath, payload, ctx.rootData);
         };
       }
     } else {
       add = () => {
-        setAtPath(ctx.rootData, discriminatorPath, item);
-        ctx.onChange(discriminatorPath, item, ctx.rootData);
+        const payload = createDefaultDataFromSchema(ctx, item);
+        setAtPath(ctx.rootData, discriminatorPath, payload);
+        ctx.onChange(discriminatorPath, payload, ctx.rootData);
       };
     }
   }
@@ -526,6 +658,7 @@ const handleArrayNode = (
       childrens: childs,
       path: ctx.path,
       label: resolveLabel(ctx, node, ctx.propertySchema) ?? 'unknown label',
+      layout: layoutForPath(ctx.path),
       add,
       del,
     },
@@ -643,6 +776,11 @@ const handleNode = (
     return handleNode(ctx, ctx.defs[refToKey(node.$ref)]);
   }
 
+  // Const only schema should not render form controls
+  if (node.const !== undefined) {
+    return [];
+  }
+
   switch (node.type) {
     case 'object':
       return handleObjectNode(ctx, node);