diff --git a/arch/arm/src/stm32/stm32g4xxx_flash.c b/arch/arm/src/stm32/stm32g4xxx_flash.c
index 67a8b11978376..6333c3a2bc5d7 100644
--- a/arch/arm/src/stm32/stm32g4xxx_flash.c
+++ b/arch/arm/src/stm32/stm32g4xxx_flash.c
@@ -187,19 +187,16 @@ static inline void flash_erase(size_t page)
 
   modifyreg32(STM32_FLASH_CR, 0, FLASH_CR_PAGE_ERASE);
 
-  /* DBANK=0, Page range 0 to 128
-   * DBANK=1, Page range 0 to 255
-   */
-
   modifyreg32(STM32_FLASH_CR, FLASH_CR_PNB_MASK,
               FLASH_CR_PNB(page));
 
 #if (defined(CONFIG_STM32_STM32G47XX) || \
      defined(CONFIG_STM32_STM32G48XX))
+  uint32_t half_npages = get_flash_npages() / 2
 
   if (getreg32(STM32_FLASH_OPTR) & FLASH_OPTR_DBANK)
     {
-      if (page <= 0x7f)
+      if (page < half_npages)
         {
           /* Select bank 1 */