diff --git a/src/util/format/u_format.c b/src/util/format/u_format.c
index ed2639ef53e..8f6defb3291 100644
--- a/src/util/format/u_format.c
+++ b/src/util/format/u_format.c
@@ -1375,13 +1375,14 @@ util_format_get_max_channel_size(enum pipe_format format)
    }
 }
 
-static uint32_t blocksizes_64kb[5][6][3] = {
+static uint32_t blocksizes_64kb[6][6][3] = {
 /*   3D              2D 1 sample      2D 2 samples     2D 4 samples      2D 8 samples   2D 16 samples) */
    { { 64, 32, 32 }, { 256, 256, 1 }, { 128, 256, 1 }, { 128, 128, 1 }, { 64, 128, 1 }, { 64, 64, 1 } }, /* 8 bits */
    { { 32, 32, 32 }, { 256, 128, 1 }, { 128, 128, 1 }, { 128, 64,  1 }, { 64, 64,  1 }, { 64, 32, 1 } }, /* 16 bits */
    { { 32, 32, 16 }, { 128, 128, 1 }, { 64,  128, 1 }, { 64,  64,  1 }, { 32, 64,  1 }, { 32, 32, 1 } }, /* 32 bits */
    { { 32, 16, 16 }, { 128, 64,  1 }, { 64,  64,  1 }, { 64,  32,  1 }, { 32, 32,  1 }, { 32, 16, 1 } }, /* 64 bits */
    { { 16, 16, 16 }, { 64,  64,  1 }, { 32,  64,  1 }, { 32,  32,  1 }, { 16, 32,  1 }, { 16, 16, 1 } }, /* 128 bits */
+   { { 16, 16, 8  }, { 64,  32,  1 }, { 32,  32,  1 }, { 32,  16,  1 }, { 16, 16,  1 }, { 16, 8,  1 } }, /* 256 bits */
 };
 
 uint32_t