diff --git a/os/hal/ports/STM32/STM32F7xx/hal_lld.c b/os/hal/ports/STM32/STM32F7xx/hal_lld.c
index 706082d57..53398d411 100644
--- a/os/hal/ports/STM32/STM32F7xx/hal_lld.c
+++ b/os/hal/ports/STM32/STM32F7xx/hal_lld.c
@@ -240,7 +240,8 @@ void stm32_clock_init(void) {
 
 #if STM32_ACTIVATE_PLLI2S
   /* PLLI2S activation.*/
-  RCC->PLLI2SCFGR = STM32_PLLI2SR | STM32_PLLI2SN;
+  RCC->PLLI2SCFGR = STM32_PLLI2SR | STM32_PLLI2SQ | STM32_PLLI2SP |
+                    STM32_PLLI2SN;
   RCC->CR |= RCC_CR_PLLI2SON;
 
   /* Waiting for PLL lock.*/
diff --git a/readme.txt b/readme.txt
index 5211bbb46..724215970 100644
--- a/readme.txt
+++ b/readme.txt
@@ -165,6 +165,8 @@
 - EX:  Updated LIS302DL to 1.1.0 (backported to 18.2.1).
 - EX:  Updated LPS25H to 1.1.0 (backported to 18.2.1).
 - EX:  Updated LSM303DLHC to 1.1.0 (backported to 18.2.1).
+- HAL: Fixed STM32F7xx I2SPLL not fully initialized (bug #992)
+       (backported to 18.2.2 and 17.6.5).
 - HAL: Fixed ethernet registry error for STM32F469/479 (bug #990)
        (backported to 18.2.2 and 17.6.5).
 - RT:  Fixed bug in chEvtBroadcastFlagsI (bug #989)