diff --git a/fusee/fusee-primary/src/sdmmc.c b/fusee/fusee-primary/src/sdmmc.c
index 68ee5df13..cce793cdb 100644
--- a/fusee/fusee-primary/src/sdmmc.c
+++ b/fusee/fusee-primary/src/sdmmc.c
@@ -1033,9 +1033,27 @@ static int sdmmc_handle_cpu_transfer(struct mmc *mmc, uint16_t blocks, bool is_w
 
             // Transfer the data to the relevant
             if (is_write) {
-                mmc->regs->buffer = *buffer;
+                if ((uintptr_t)buffer & 3) {
+                    // Handle unaligned buffers
+                    uint32_t w;
+                    uint8_t *data = (uint8_t *)buffer;
+                    w = data[0] | (data[1] << 8) | (data[2] << 16) | (data[3] << 24);
+                    mmc->regs->buffer = w;
+                } else {
+                    mmc->regs->buffer = *buffer;
+                }
             } else {
-                *buffer = mmc->regs->buffer;
+                if ((uintptr_t)buffer & 3) {
+                    // Handle unaligned buffers
+                    uint32_t w = mmc->regs->buffer;
+                    uint8_t *data = (uint8_t *)buffer;
+                    data[0] = w & 0xFF;
+                    data[1] = (w >> 8) & 0xFF;
+                    data[2] = (w >> 16) & 0xFF;
+                    data[3] = (w >> 24) & 0xFF;
+                } else {
+                    *buffer = mmc->regs->buffer;
+                }
             }
 
             // Advance by a register size...
diff --git a/fusee/fusee-secondary/src/sdmmc.c b/fusee/fusee-secondary/src/sdmmc.c
index 68ee5df13..cce793cdb 100644
--- a/fusee/fusee-secondary/src/sdmmc.c
+++ b/fusee/fusee-secondary/src/sdmmc.c
@@ -1033,9 +1033,27 @@ static int sdmmc_handle_cpu_transfer(struct mmc *mmc, uint16_t blocks, bool is_w
 
             // Transfer the data to the relevant
             if (is_write) {
-                mmc->regs->buffer = *buffer;
+                if ((uintptr_t)buffer & 3) {
+                    // Handle unaligned buffers
+                    uint32_t w;
+                    uint8_t *data = (uint8_t *)buffer;
+                    w = data[0] | (data[1] << 8) | (data[2] << 16) | (data[3] << 24);
+                    mmc->regs->buffer = w;
+                } else {
+                    mmc->regs->buffer = *buffer;
+                }
             } else {
-                *buffer = mmc->regs->buffer;
+                if ((uintptr_t)buffer & 3) {
+                    // Handle unaligned buffers
+                    uint32_t w = mmc->regs->buffer;
+                    uint8_t *data = (uint8_t *)buffer;
+                    data[0] = w & 0xFF;
+                    data[1] = (w >> 8) & 0xFF;
+                    data[2] = (w >> 16) & 0xFF;
+                    data[3] = (w >> 24) & 0xFF;
+                } else {
+                    *buffer = mmc->regs->buffer;
+                }
             }
 
             // Advance by a register size...